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How does a balanced chemical equation satisfy the Law of Conservation of Mass?
During a chemical reaction, the total amount of matter stays the same.
During a chemical reaction, matter is destroyed.
During a chemical reaction, one or more new substances are formed.
During a chemical reaction, the total number of atoms increases.
When 5 grams of silver nitrate are added to a 50 gram solution of potassium chloride, 2 grams of silver chloride form in the solution as a precipitate. After the reaction, the total mass of the solution is 55 grams. Which evidence from the experiment supports the law of conservation of mass?
The final mass of the product equals the mass of the reactants.
The final mass of the product is less than the mass of the reactants.
The mass of the precipitate is less than the amount of silver nitrate.
The mass of the precipitate is greater than the amount of silver nitrate.
A scientist placed a sample of lithium into a container of water. The scientist observed the lithium floating and making a buzzing sound as gas bubbles were forming around it. Which conclusion is BEST supported by this observation?
A chemical change took place.
The lithium was dissolved by the water.
Dissolved gases were released.
Water was vaporized.
Which statement best explains how the periodic table is organized?
increasing atomic number from left to right
increasing number of neutrons from left to right
decreasing number of electrons from left to right
decreasing atomic mass number from left to right
Where are the most reactive nonmetals located on the periodic table?
the uppermost complete row of the table
the rows at the bottom of the table connecting two sections
the column at the far left side of the table
the second column from the right side of the table
Mg(OH)2 is a compound. How many different elements are found in this compound?
Which equation is balanced according to the Law of Conservation of Mass?
NaCl + Mg → MgCl2 + Na
2NaCl + Mg → MgCl2 + Na
2NaCl + Mg → MgCl2 + 2Na
A student mixed 10 grams of a powdery substance with 200 grams of an acid solution. A bubbly solution weighing 205 grams was formed. Which best explains why the mass of the new solution does not equal the mass of the reactants?
The other 5 grams changed color.
The other 5 grams created a precipitate.
The other 5 grams were released as a gas.
The other 5 grams weighed less in the acid.
The chemical formula for baking soda is NaHCO3. How many different elements make up baking soda?
Which best represents a balanced equation?
HgO --> Hg + O2
2Fe + O2 --> Fe2O3
2H2 + O2 --> 2H2O
3P + 5O2 ----> P410