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- 1. Multiple Choice
When sodium atoms (Na) and chlorine atoms (Cl) join to make sodium chloride, or table salt, they form an ionic bond. Using this information, which pair of elements is most likely to form an ionic bond?
potassium (K) and fluorine (F)
aluminum (Al) and aluminum (Al)
sulfur (S) and oxygen (O)
calcium (Ca) and neon (Ne)
- 2. Multiple Choice
Based on the location of nitrogen (N) on the periodic table, how many additional electrons does a nitrogen atom need in its valence shell to satisfy the octet rule when it forms bonds?
1
3
5
8
- 3. Multiple Choice
Helium (He) and neon (Ne) are elements in Group 8A of the periodic table. How do the electron dot diagrams of these elements compare?
The electron dot diagram of helium has six fewer dots than the electron dot diagram of neon.
The electron dot diagram of helium has eight fewer dots than the electron dot diagram of neon.
Both the electron dot diagram of helium and the electron dot diagram of neon have two dots.
Both the electron dot diagram of helium and the electron dot diagram of neon have eight dots.
- 4. Multiple Choice
Which is a force that holds atoms together?
chemical bond
electron shell
valence electron
chemical formula
- 5. Multiple Choice
Metal atoms tend to give away valence electrons when they bond with nonmetal atoms. What type of bond will form between the metal and nonmetal atoms and why does this bond form?
A covalent bond will form because electrons are transferred.
An ionic bond will form because electrons are transferred.
A covalent bond will form because electrons are shared.
An ionic bond will form because electrons are shared.
- 6. Multiple Choice
The electron dot diagram shows the arrangement of dots without identifying the element.
Which element’s symbol could replace the question mark in the diagram?
carbon (C)
tellurium (Te)
beryllium (Be)
cesium (Cs)
- 7. Multiple Choice
Atoms of which elements form bonds without satisfying the octet rule?
potassium (K) and sodium (Na)
neon (Ne) and argon (Ar)
nitrogen (N) and fluorine (F)
helium (He) and hydrogen (H)
- 8. Multiple Choice
The electron dot diagram shows the arrangement of dots without identifying the element.
Which element’s symbol could replace the question mark in the diagram?
boron (B)
neon (Ne)
rubidium (Rb)
arsenic (As)
- 9. Multiple Choice
Lead is malleable, so it can be pounded into flat sheets without breaking. How does the bonding within lead help to explain this property?
Metallic bonds involve valence electrons that are removed from one atom and given to another, so the pounding helps the electrons move.
Covalent bonds involve valence electrons that are shared between two metal atoms, so the bonds are strong enough to resist the pounding.
Metallic bonds involve many valence electrons shared by many atoms, so the bonds can move around as the metal is pounded.
Covalent bonds involve valence electrons that are removed from one atom and given to another, so the pounding helps the electrons move.
- 10. Multiple Choice
Hee Sun drew an electron dot diagram of a silicon atom as shown.
In addition to changing the symbol to C, how would this diagram compare with an electron dot diagram of a carbon atom (C)?
The dot to the left of the symbol would be removed in the diagram for carbon.
The same number of dots would appear in the diagram for carbon.
There would be two dots above and to the right of the symbol in the diagram for carbon.
The single dots would be replaced with two dots on each side of the symbol in the diagram for carbon.
- 11. Multiple Choice
This chart shows characteristics of three different types of atoms.
Which statement is best supported by the information in the chart?
Atom X will donate electrons to Atom Y.
Atom X will accept electrons from Atom Y.
Atom Y will accept electrons from Atom Z.
Atom Z will donate electrons to Atom X.
- 12. Multiple Choice
Which shows the correct order of steps during the formation of an ionic bond?
Ions are attracted to each other → Electrons are transferred → An ionic compound forms
An ionic compound forms → Ions are attracted to each other → Electrons are transferred
Electrons are transferred → Ions form → Ions are attracted to each other
Ions form → Electrons are transferred → Ions are attracted to each other
- 13. Multiple Choice
Which two elements will most likely form an ionic bond? (Click on the periodic table icon to view these elements)
krypton and lithium
magnesium and bromine
calcium and potassium
iodine and chlorine
- 14. Multiple Choice
Ionic compounds form
crystal structures.
molecular structures.
pure elements.
neutral elements.
- 15. Multiple Choice
Chalk is an ionic compound. Which is a property of all ionic compounds that makes chalk particularly useful for writing on a chalkboard?
a high melting point
hardness and brittleness
inability to dissolve in water
a multicolored appearance
- 16. Multiple Choice
Which characteristic(s) makes ionic compounds useful as a building material?
low melting and boiling points
hardness and brittleness
inability to conduct electricity
inability to dissolve in water
- 17. Multiple Choice
Alice added sodium chloride to water and stirred the water for several minutes. Alice is most likely trying to demonstrate that ionic compounds
are hard.
can dissolve.
are clear.
can melt.
- 18. Multiple Choice
What will most likely occur if sulfur forms an ionic bond with another element? (Click on the icon for the periodic table to view sulfur)
Sulfur will accept electrons.
Sulfur will donate electrons.
Sulfur will become a positive ion.
Sulfur will become less stable.
- 19. Multiple Choice
What is formed when polyatomic ions bond with other ions?
ionic compounds
neutral compounds
ionic elements
neutral elements
- 20. Multiple Choice
Which is an example of a polyatomic ion?
H2
CO3-
Mg+
Ne+ -
- 21. Multiple Choice
Why can a hydrogen atom form a covalent bond without fulfilling the octet rule?
Hydrogen’s valence shell can hold only up to two electrons.
Hydrogen’s valence shell never needs to be full to be stable.
The octet rule only applies to bonds formed by trading electrons.
The octet rule only applies to alkali metals and alkaline earth metals.
- 22. Multiple Choice
For a science fair project about food and chemistry, Bill looks around his kitchen for examples of covalent compounds. What evidence can Bill use in his project to show that water (H2O) acts like other covalent compounds?
He can demonstrate that water is a liquid with a definite volume.
He can demonstrate that water can be boiled on a simple kitchen stove.
He can demonstrate that water can sometimes be used to conduct electricity.
He can demonstrate that water can change shape and either be sprayed or poured.
- 23. Multiple Choice
Covalent bonds can be best described as
neutral atoms coming together to share electrons.
neutral atoms coming together to create electrons.
ionized atoms coming together to trade electrons.
ionized atoms coming together to destroy electrons.
- 24. Multiple Choice
A candle’s wick is the fabric string that holds the flame, and it burns down at a constant slow pace when the candle is lit. The wick is usually surrounded by wax.
Which is the most important property of covalent compounds that makes them useful for making candle wax?
a low boiling point
a low melting point
a high boiling point
a high melting point
- 25. Multiple Choice
The compound cyanogen (CN)2 has covalent bonds shown in this diagram.
How many electrons are shared between one nitrogen atom and one carbon atom?
2
3
6
7
- 26. Multiple Choice
Walls made of paraffin wax, a covalent compound, help keep the temperature in a room steady as night changes into day and day into night. What is the most important property of covalent compounds that allows paraffin wax to help keep a room’s temperature level?
The wall would not absorb or release any heat energy from the room or outside, so it would not affect the room’s temperature.
The wall would not absorb heat during the day, but at night it would release heat that naturally exists inside of most covalent compounds.
The wall would absorb extra heat during the day when the sun is out, then release the heat back into the room when the sun goes down.
The wall would absorb extra heat during the day, and the wall would hold this heat in so that it cannot absorb any more heat from the night air.
- 27. Multiple Choice
Which element can join with other elements to form covalent bonds?
beryllium (Be)
carbon (C)
cesium (Cs)
iron (Fe)
- 28. Multiple Choice
The compound ethylene (C2H4) is represented by this diagram.
What statement best describes the arrangement of the atoms in an ethylene molecule?
Each carbon atom shares two electrons with one hydrogen atom and also shares two electrons with the other carbon atom.
Each carbon atom shares four electrons with one hydrogen atom and also shares four electrons with the other carbon atom.
One electron is shared between each hydrogen atom and the carbon atom bonded to it, and two electrons are shared between the carbon atoms.
Two electrons are shared between each hydrogen atom and the carbon atom bonded to it, and four electrons are shared between the carbon atoms.
- 29. Multiple Choice
Which is most likely a covalent compound?
NaCl
KCl
CuF2
CF4
- 30. Multiple Choice
Phosphorous (P) and chlorine (Cl) bond covalently to form the important industrial compound phosphorous trichloride. The diagrams below show the electron structures of phosphorous and chlorine.
Which diagram shows how the covalent bonds most likely form in a phosphorous trichloride molecule?
- 31. Multiple Choice
Why can a hydrogen atom form a covalent bond without fulfilling the octet rule?
Hydrogen’s valence shell can hold only up to two electrons.
Hydrogen’s valence shell never needs to be full to be stable.
The octet rule only applies to bonds formed by trading electrons.
The octet rule only applies to alkali metals and alkaline earth metals.
- 32. Multiple Choice
What best explains how two oxygen atoms, each with six valence electrons, can bond with each other?
One atom can lose two electrons so that the other atom can gain them and have eight valence electrons.
One atom can lose four electrons to the environment so that a total of eight valence electrons remains.
Each atom can share two electrons with the other so that each atom has eight valence electrons.
Each atom can lose two electrons so that there is a total of eight valence electrons between the atoms.
- 33. Multiple Choice
In carbon dioxide (CO2), there are two oxygen atoms for each carbon atom. Each oxygen atom forms a double bond with carbon, so the molecule is formed by two double bonds.
Two double bonds means that the total number of electrons being shared in the molecule is
2
4
6
8
- 34. Multiple Choice
Which best describes most covalent compounds?
resilient
brittle
cold
warm
- 35. Multiple Choice
Which of these is a compound?
O
CO2
O2
CO
- 36. Multiple Choice
How many atoms of nitrogen are in the chemical formula Ni(NO3)2?
2
1
6
3
- 37. Multiple Choice
How many atoms of each element are in the chemical formula P2O5?
2 phosphorus and 5 oxygen
5 phosphorus and 2 oxygen
1 phosphorus and 5 oxygen
2 phosphorus and 1 oxygen
- 38. Multiple Choice
Which statement describes how chemical formulas, such as H2O, represent compounds?
They show the types of molecules that make up an atom.
They show the elements that make up a compound.
They show the three-dimensional shape of a molecule.
They show the types of bonds that exist between elements.
- 39. Multiple Choice
Which statement correctly describes why a compound is a pure substance?
A compound is not a pure substance because each of its molecules is made up of the atoms of two or more different elements.
A compound is a pure substance because its molecule cannot be broken down into simpler particles by physical means.
A compound is not a pure substance because it is not an element, and only elements are pure substances.
A compound is a pure substance because it consists of two different elements, which are pure substances.
- 40. Multiple Choice
There are several ways to model a compound. One type of model is shown.
What is the chemical formula for the molecule modeled?
CHO
C4H11O2
C6H12O2
C6H9O
- 41. Multiple Choice
There are several different models that represent compounds. One type of model is shown.
What type of model is shown?
a structural formula
a chemical formula
a space-filling model
a ball-and-stick model
- 42. Multiple Choice
What does the chemical formula CaCl2 show about the compound it represents?
It is made up of one element.
It is made up of two elements.
It is made up of three elements.
It is made up of four elements.
- 43. Multiple Choice
Which is the best description of a molecule?
A molecule of an element is composed of at least two types of atoms.
A molecule of a compound is composed of only one type of atom.
A molecule of a compound is composed of at least two types of atoms.
A molecule of an element is composed of exactly two types of atoms.
- 44. Multiple Choice
How many atoms of oxygen in the chemical formula 2Ca(ClO2)2?
2
4
6
8
- 45. Multiple Choice
Two chemicals react in an endothermic reaction. What can be known about this reaction?
The new substance will need more energy to form its chemical bonds than the old substance will release.
More energy will be released from the old substance than the new substance will need to form its chemical bonds.
A precipitate will form as a result of the reaction.
A gas will form as a result of the reaction.
- 46. Multiple Choice
A Venn diagram is used to compare and contrast different topics. The items that are unique to each topic are represented in the separate sections of the circles, and the items that are common to both topics are represented in the center overlapping sections. Harlow creates this Venn diagram comparing and contrasting endothermic and exothermic processes.
What can be added to the Examples section of each circle?
Endothermic: ice melting into water, and a heat pack becoming warm
Exothermic: a glow stick glowing, and fireworks exploding
Endothermic: ice melting into water, and an instant ice pack turning cold
Exothermic: fireworks exploding, and gasoline burning
Endothermic: a glow stick glowing, and a heat pack becoming warm
Exothermic: an instant ice pack turning cold, and ice melting into water
Endothermic: gasoline burning, and an instant ice pack turning cold
Exothermic: ice melting into water, and an instant ice pack turning cold
- 47. Multiple Choice
For a science project, Janet performs four experiments that are supposed to show a chemical reaction. She displays her results in a table.
In the column titled "Chemical reaction?,” which experiment’s data should be changed to "No”?
Experiment 1
Experiment 2
Experiment 3
Experiment 4
- 48. Multiple Choice
Cherylanne mixes together Chemical A and Chemical B in a test tube, forming Chemical C. The mixture instantly turns cool to the touch. She then adds Chemical D, and the reaction becomes hot and explodes.
What can be known about this situation?
Chemicals A and B form an endothermic reaction, and chemicals C and D form an exothermic reaction.
Chemicals A and B form an exothermic reaction, and chemicals C and D form an endothermic reaction.
Chemicals A and C form an endothermic reaction, and chemicals B and D form an exothermic reaction.
Chemicals A and B form an exothermic reaction, and chemicals B and D form an endothermic reaction.
- 49. Multiple Choice
When vinegar and baking soda react, the mixture becomes cold to the touch and a gas and a new liquid substance are formed.
Which best describes what is occurring in the reaction?
The reaction is non-chemical and exothermic.
The reaction is chemical and endothermic.
The reaction is non-chemical and endothermic.
The reaction is chemical and exothermic.
- 50. Multiple Choice
Pedro wants to create a chemical reaction between oil and water. He adds oil to a beaker of water and notices that the liquids do not mix. He then shakes the beaker and the drops of oil become suspended through the water for a few moments before returning to their separate layers.
Did Pedro succeed in creating a chemical change?
Yes, because the oil was evenly suspended.
Yes, because the solution was permanently changed.
No, because the oil only briefly mixed with the water.
No, because no new substances were formed.
- 51. Multiple Choice
Reggie and Charlotte are baking oatmeal cookies. They dip the baked cookies in melted chocolate. The chocolate cools to form a hardened coating. Reggie argues the entire chocolate-covered cookie has undergone a chemical change. Charlotte disagrees, saying only the original oatmeal cookie has undergone a chemical change, not the chocolate coating.
Who is correct?
Reggie, because baking and melting cause bonds to be broken, leading to a chemical change.
Reggie, because objects that are heated always undergo chemical changes.
Charlotte, because melting objects only sometimes cause a chemical change.
Charlotte, because baking causes a chemical change, but melting objects is a non-chemical change.
- 52. Multiple Choice
What must occur in order for a chemical reaction to be specifically classified as endothermic instead of exothermic?
Atoms are rearranged.
Chemical bonds are formed.
Energy is released in the form of heat.
Energy is absorbed in the form of heat.
- 53. Multiple Choice
Which is an example of a chemical reaction?
paper folded into tiny pieces
paper burned and turned into smoke
paper soaked in water
paper shredded and turned into pulp
- 54. Multiple Choice
Which of these most likely represents a chemical change?
water boiling
sugars digested by saliva
mud drying to dirt
ice cream melting
- 55. Multiple Choice
When liquid silver nitrate and liquid sodium chloride are combined, solid silver chloride forms along with a new liquid, sodium nitrate. Which substance represents the precipitate?
silver nitrate
silver chloride
sodium chloride
sodium nitrate
- 56. Multiple Choice
Theresa creates an experiment where she mixes two red-colored substances together in a container and observes the solution slowly changing from red to blue for the next eight minutes. The solution becomes completely blue after eight minutes.
What does this represent about the type of change happening in the container?
A chemical change started immediately and finished at eight minutes.
A non-chemical change started immediately and finished at eight minutes.
A chemical change occurred at four minutes.
A non-chemical change occurred at four minutes.
- 57. Multiple Choice
What must occur in order for a chemical reaction to be specifically classified as endothermic instead of exothermic?
Atoms are rearranged.
Chemical bonds are formed.
Energy is released in the form of heat.
Energy is absorbed in the form of heat.
- 58. Multiple Choice
When baking soda and vinegar react, the surface bubbles. What does this most likely indicate?
a chemical change, because a precipitate is being formed
a chemical change, because a gas is being formed
a non-chemical change, because a precipitate is being formed
a non-chemical change, because a gas is being formed
- 59. Multiple Choice
Cherylanne mixes together Chemical A and Chemical B in a test tube, forming Chemical C. The mixture instantly turns cool to the touch. She then adds Chemical D, and the reaction becomes hot and explodes.
What can be known about this situation?
Chemicals A and B form an endothermic reaction, and chemicals C and D form an exothermic reaction.
Chemicals A and B form an exothermic reaction, and chemicals C and D form an endothermic reaction.
Chemicals A and C form an endothermic reaction, and chemicals B and D form an exothermic reaction.
Chemicals A and B form an exothermic reaction, and chemicals B and D form an endothermic reaction.
- 60. Multiple Choice
Which is an example of a chemical reaction?
paper folded into tiny pieces
paper burned and turned into smoke
paper soaked in water
paper shredded and turned into pulp
- 61. Multiple Choice
Which best describes what happens to the atoms in a chemical reaction?
they are rearranged
many of them disappear
all of them form stronger bonds
all of them remain unchanged
- 62. Multiple Choice
Which best explains why a firework being ignited is an example of an exothermic reaction and not an endothermic reaction?
The fireworks produce colors.
The fireworks give off heat.
Igniting the fireworks requires energy.
Igniting the fireworks makes an odor.
- 63. Multiple Choice
Which is evidence that a chemical reaction has likely occurred?
a liquid slowly losing volume
the formation of a precipitate
boiling water releasing steam
a change in the shape of a solid
- 64. Multiple Choice
Which is the correctly balanced equation for the reaction of rust, Fe2O3, and hydrochloric acid, HCl?
Fe2O3 + HCl → FeCl3 + H2O
Fe2O3 +3 HCl → 2 FeCl3 + H2O
Fe2O3 + 6 HCl → 2 FeCl3 + 3 H2O
Fe2O3 + 3 HCl → 2 FeCl3 + 3 H2O
- 65. Multiple Choice
Liquid 1 reacts with Liquid 2, producing a solid and a gas. Using this scenario, which supports the law of conservation of mass?
mass of Liquid 1 + mass of solid = mass of Liquid 2 + mass of gas
mass of Liquid 1 – mass of solid = mass of Liquid 2 – mass of gas
mass of Liquid 1 – mass of Liquid 2 = mass of solid + mass of gas
mass of Liquid 1 + mass of Liquid 2 = mass of solid + mass of gas
- 66. Multiple Choice
Leslie incorrectly balances an equation as 2C4H10 +12O2 → 8CO2 + 10H2O.
Which coefficient should she change?
2
8
10
12
- 67. Multiple Choice
What can the arrow in a chemical reaction be translated to mean? Check all that apply.
yields
accompanied by
react to form
added to
except
- 68. Multiple Choice
The product side of a chemical reaction is shown.
→ 7Ti2(SO4)3
Which number represents a coefficient?
2
3
4
7
- 69. Multiple Choice
What is the number “4” in SiCl4?
a subscript
a coefficient
a product
a reactant
- 70. Multiple Choice
In the product 6O2, what does the coefficient mean?
There are 12 molecules of O2,
There are 8 molecules of O2,
There are 6 molecules of O2.
There are 2 molecules of O2.
- 71. Multiple Choice
In a process called photosynthesis, plants use carbon dioxide and water, along with energy from sunlight, to produce sugar and oxygen. Photosynthesis is represented by the equation
What must a plant need to produce 4 molecules of sugar?
6 molecules of CO2
6 molecules of H2O
18 molecules of CO2
24 molecules of H2O
- 72. Multiple Choice
Franklin was performing an experiment by combining hydrochloric acid and sodium hydroxide. He measured the mass of his reactant materials to be 35g. The reaction resulted in the production of salt and water. He reported that his products weighed 32g.
Which best describes the results of Franklin’s experiment?
No error occurred, some of the products are always lost as heat.
An error occurred, the mass of the reactants should equal the mass of the products.
An error occurred, the products should weigh more than the reactants.
No error occurred, water is not weighed when determining the weight of the products.
- 73. Multiple Choice
Which best represents the law of conservation of mass?
mass of reactants > mass of products
mass of reactants < mass of products
mass of reactants = mass of products
mass of reactants → mass of products
- 74. Multiple Choice
Cecil writes the equation for the reaction of hydrogen and oxygen below.
H2 + O2 → H2O
Why does his teacher ask him to balance the equation by including the correct coefficients?
to show that most molecules exist in pairs
to show that most compounds exist in pairs
to show that atoms are conserved in chemical reactions
to show that atoms are created in chemical reactions
- 75. Multiple Choice
Which additional product balances the reaction H2SO4 + 2NaOH → Na2SO4 + ________?
2H2O
2OH
H2O2
H3O
- 76. Multiple Choice
Min is asked to balance the equation below.
Original: Ca3P2 + H2O → Ca(OH)2 + PH3
Min’s result: Ca3P2 + H2O → Ca3(OH)2 + PH3
Which best describes Min’s method for balancing the chemical equation?
It is correct, because now there are three Ca atoms on each side of the equation.
It is incorrect, because the identity of the original product has changed.
It is correct, because Ca3(OH)2 creates a more stable compound.
It is incorrect, because the subscript “2” should be added instead.
- 77. Multiple Choice
Which is the balanced equation for V2O5 + CaS → CaO + V2S5?
V2O5 + CaS → CaO + V2S5
5V2O5 + 5CaS → 10CaO + 5V2S5
3V2O5 + 3CaS → 3CaO + 3V2S5
V2O5 + 5CaS → 5CaO + V2S5
- 78. Multiple Choice
Plants use sunlight as energy to convert carbon dioxide and water into glucose and oxygen. Which best describes the reaction?
The law of conservation of mass indicates the same amount of carbon will be found in the reactants as in the products.
The law of conservation of energy indicates the same amount of carbon will be found in the reactants as in the products.
The law of conservation of mass indicates the same amount of glucose will be found in the reactants as in the products.
The law of conservation of energy indicates the same amount of glucose will be found in the reactants as in the products.
- 79. Multiple Choice
Which equation is balanced?
Mg3N2 + H2O 3MgO + 2NH3
C3H8 + 5O2 H2O + 3CO2
Zn + 2HCl ZnCl2 + H2
3H2SO4 + 2Fe Fe2(SO4)3 + H2
- 80. Multiple Choice
Lana balanced an equation so that the result was 2C2H3Br + 5O2 → 4CO2 + 2H2O + 2HBr. Which most likely represents the starting equation?
2C4H3Br + 5O2 → 4CO2 + 2H2O + 2HBr
C2H3Br + 5O2 → 4CO2 + H2O + 2HBr
C4H3Br + O2 → CO2 + H2O + HBr
C2H3Br + O2 → CO2 + H2O + HBr
- 81. Multiple Choice
The amount of oxygen in the reactants is 4 atoms. In the products, the oxygen is distributed to water (H2O) and O2 gas. Which coefficients would be placed in front of water and oxygen?
2 in front of water and 2 in front of oxygen
1 in front of water and 2 in front of oxygen
1 in front of water and 1 in front of oxygen
2 in front of water and 1 in front of oxygen
- 82. Multiple Choice
One half of a balanced chemical equation is shown.
3Mg(OH)2 + 2H3PO4
Which lists the numbers of each atom the other half of the equation would contain?
3 Mg, 2 P, 14 O, 12 H
Mg, 2 P, 14 O, 6 H
3 Mg, 8 P, 7 O, 6 H
6 Mg, 6 P, 2 O, 12 H
- 83. Multiple Choice
The equation below is for potassium oxide.
4K + O2 2K2O
What is the ratio of atoms of potassium to atoms of oxygen?
1:2
2:1
4:1
1:4
- 84. Multiple Choice
The equations are not balanced. Which equation would have the same coefficients in the same order as 2CO2 +3H20 C2H6O + 3O2?
FeCl3 + NH4OH Fe(OH)3 + NH4Cl
CH4 + O2 CO2 + H2O
Fe + H2SO4 Fe2(SO4)3 + H2
PCl5 + H2O HCl + H3PO4
- 85. Multiple Choice
Which best describes the law of conservation of mass?
The coefficients in front of the chemicals in the reactants should be based on the physical state of the products.
Products in the form of gases are not considered a part of the total mass change from reactants to products.
When reactants contain both a solid and a liquid, the solid counts toward the overall mass and the liquid does not.
The mass of the reactants and products is equal and is not dependent on the physical state of the substances.
- 86. Multiple Choice
Charlie is balancing an equation. She has identified the atoms and counted the number of each in the reactants and products. What would Charlie adjust to make the number of atoms in the reactants the same as the number of atoms in the products?
coefficients
subscripts
superscripts
parentheses
- 87. Multiple Choice
If the mass of the products measured 120 g, what would be the mass of the reactants?
30g
60g
120g
240g
- 88. Multiple Choice
Akia is balancing the equation Na + H2O NaOH + H2. He tries to find the coefficients that will balance the equation.
How could he find the correct coefficients?
by counting each individual atom and making sure the number of each kind of atom is the same in the reactants and the products
by counting the total atoms and making sure the number of atoms in the reactants is the same as the number of atoms in the products
by counting the total mass of each compound and making sure the reactants have more mass than the products
by counting the mass of each atom and making sure the reactants are more massive than the products
- 89. Multiple Choice
Which best describes the law of conservation of mass?
The coefficients in front of the chemicals in the reactants should be based on the physical state of the products.
Products in the form of gases are not considered a part of the total mass change from reactants to products.
When reactants contain both a solid and a liquid, the solid counts toward the overall mass and the liquid does not.
The mass of the reactants and products is equal and is not dependent on the physical state of the substances.
- 90. Multiple Choice
Which type of reaction is NaCl + AgNO3 → NaNO3 + AgCl?
synthesis
decomposition
oxidation
replacement
- 91. Multiple Choice
Which clue can be used to identify a chemical reaction as a replacement reaction?
The reaction has two reactants with ions that seem to switch places.
The reaction has a single reactant that changes into two or more products.
The reaction involves oxygen reacting with a hydrocarbon and giving off heat.
The reaction involves a single product forming from two or more reactants.
- 92. Fill in the Blank
What else is produced when sodium carbonate decomposes?
Na2CO3 → Na2O +
- 93. Multiple Choice
When Coach Kwan notices that a player is getting tired, she takes out the tired player and substitutes a fresh player. Which type of chemical reaction does this best model?
replacement
decomposition
synthesis
oxidation
- 94. Fill in the Blank
What else is produced during the combustion of propane, C3H8?
C3H8 + 5O2 → 3CO2 + 4_____
- 95. Multiple Choice
A product that is a chemically bonded combination of reactants will form in which type of reaction? Select three options.
synthesis
polymerization
decomposition
oxidation
replacement
- 96. Multiple Choice
Luis is helping his parents paint a border around the walls of a room. He uses a stencil to repeat the same design on each wall to form one long grapevine with a bunch of grapes every foot along its length. What type of chemical reaction does this best model?
replacement
decomposition
polymerization
synthesis
- 97. Multiple Choice
What is produced during the replacement reaction of Ba(NO3)2 and Na2SO4?
2BaNa + 2NO3SO4
2NaNO3 + BaSO4
NaNO3 + BaSO4
BaNa2 + (NO3)2SO4
- 98. Multiple Choice
Which is produced in a synthesis reaction?
a single element
a single compound
a single ion
a single atom
- 99. Multiple Choice
Rosa was looking for patterns to help predict the products of chemical reactions. She recorded three similar decomposition reactions in the table.
What products should she record in the last row of the table?
2LiCl + 3O2
3LiCl + 2O2
2LiO + 3Cl2
3LiO+ 2Cl2
- 100. Multiple Choice
Andre is predicting the products of chemical reactions. In one reaction, a hydrocarbon is the only reactant. What is the best prediction and explanation of this reaction?
Two new compounds form as the hydrocarbon undergoes a synthesis reaction.
Carbon dioxide and water form because the hydrocarbon undergoes a combustion reaction.
A polymer forms because the hydrocarbon joins with itself in a polymerization reaction.
Oxides form because the hydrocarbon combines with oxygen in an oxidation reaction.
- 101. Multiple Choice
When explaining chemical reactions to a friend, Brianna models a reaction by taking several colors of modeling clay and making a sculpture of a horse. Which type of chemical reaction is Brianna most likely explaining?
synthesis
decomposition
polymerization
replacement
- 102. Multiple Choice
A chemical reaction that has the general formula of AB + C → CB + A is best classified as a _____________ reaction.
synthesis
polymerization
decomposition
oxidation
replacement
- 103. Multiple Choice
Fluorine has an atomic number 9. It is in period 2 of the periodic table. The diagram shows the electron dot diagram of a fluorine atom.
How many valence electrons are in an atom of fluorine?
2
7
9
17
- 104. Multiple Choice
Which best represents the reaction of calcium and zinc carbonate (ZnCO3) to form calcium carbonate (CaCO3) and zinc?
Ca → ZnCO3 + CaCO3 → Zn
Ca + ZnCO3 → CaCO3 + Zn
CaCO3 + Zn → Ca + ZnCO3
CaCO3 + Zn + Ca → ZnCO3
- 105. Multiple Choice
Which type of reaction is Mg + S → MgS?
polymerization
synthesis
replacement
decomposition
- 106. Multiple Choice
Giovanni created this chart to study for an exam.
Which best describes how to correct the error in the chart?
Remove “plastics” from the uses for sodium hydroxide.
Swap the uses for iron oxide and calcium carbonate.
Change the use for calcium chloride to “used in preservatives.”
Add “de-ice roads” to uses for calcium carbonate.
- 107. Multiple Choice
Lars is balancing equations with his study group. He is unsure about one equation because each member of the study group came up with a different answer. Which is the proper way to balance the equation Ca(OH)2 + H3PO4 → Ca3(PO4)2 + H2O?
Ca(OH)2 + H3PO4 → Ca3(PO4)2 + 6H2O
3Ca(OH)2 + 2H3PO4 → Ca3(PO4)2 + 3H2O?
3Ca(OH)2 + 2H3PO4 → Ca3(PO4)2 + 6H2O?
Ca(OH)2 + 2H3PO4 → Ca3(PO4)2 + 6H2O?
- 108. Multiple Choice
For the equation BaCl2 + Na2SO4 → BaSO4 + 2NaCl, how many chlorine atoms are on the reactants side and on the products side?
reactants: 1; products: 1
reactants: 1; products: 2
reactants: 2; products: 1
reactants: 2; products: 2
- 109. Multiple Choice
How do the nuclei of covalently bonded atoms help keep the bond together?
Neutral particles in the nucleus provide enough mass that the force of gravity holds the atoms together.
Neutral particles in the nucleus can become positive or negative in order to balance the charges.
Positive particles in the nucleus change into negative particles that enter electron shells.
Positive particles in the nucleus are attracted to shared electrons, so the atoms stay close together.
- 110. Multiple Choice
What does the chemical formula C3H6O2 tell about a molecule of the compound it represents?
It is made up of 3 atoms of 11 different elements.
It is made up of 11 atoms joined in a straight line.
It is made up of 11 total atoms of 3 different elements.
It is made up of 1 atom composed of 3 different elements.
- 111. Multiple Choice
Which element is least likely to form chemical bonds?
phosphorus (P)
helium (He)
sodium (Na)
carbon (C)
- 112. Multiple Choice
Which is the only element in group 1 on the periodic table that forms covalent bonds?
hydrogen
lithium
potassium
sodium
- 113. Multiple Choice
Which statement best describes the difference between endothermic and exothermic reactions?
They are opposites because endothermic reactions require energy and exothermic reactions release energy.
They are opposites because endothermic reactions release energy and exothermic reactions require energy.
They the same because they are both ways of forming precipitates.
They the same because they are both ways of forming gasses.
- 114. Multiple Choice
Suna passes an electric current through a sample of clear, colorless, and odorless liquid. As the experiment continues, bubbles form, and the volume of liquid decreases. Suna collects samples of two colorless, odorless gases that bubble out of the liquid. One of the gases burns. Neither the original liquid nor the other gas burns.
Which is the best explanation of her results?
The sample was broken down by the electric current and formed a new substance that could burn. Therefore, the original liquid is a compound.
The sample lost some of its volume, but the gas still had the same chemical makeup as the original sample. Therefore, the original liquid is an element.
The electric current released a gas that was odorless and colorless, like the original sample. Therefore, the original liquid is an element.
The electric current changed some of the sample to gas even though the sample was not breaking down. Therefore, the original liquid is a compound.
- 115. Multiple Choice
What else is produced during the replacement reaction of magnesium and hydrochloric acid?
Mg + 2HCl H2 + ________
MgCl2
Mg2Cl2
Mg2Cl
MgCl
- 116. Multiple Choice
The element sulfur (S) is most likely to form covalent bonds with the element
helium (He).
magnesium (Mg).
zinc (Zn).
oxygen (O).
- 117. Multiple Choice
Atoms of iron (Fe) form metallic bonds with other iron atoms. How are the valence electrons of these atoms rearranged to form the bonds?
A few valence electrons are shared between the atoms.
Many valence electrons are shared between the atoms.
Electrons are transferred from the iron atoms to atoms in the air.
Electrons are transferred to the iron atoms from atoms in the air.
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