20 questions
The three nuclides, U-233, U-235, and U-238, are isotopes of uranium because they have the same number of protons per atom and
the same number of electrons per atom
the same number of neutrons per atom
a different number of electrons per atom
a different number of neutrons per atom
Which numerical setup can be used to calculate the atomic mass of gallium?
(0.6011)(68.926 u) + (0.3989)(70.925 u)
(60.11)(68.926 u) + (39.89)(70.925 u)
(0.6011)(70.925 u) + (0.3989)(68.926 u)
(60.11)(70.925 u) + (39.89)(68.926 u)
Which list of elements is arranged in order of increasing electronegativity?
Be, Mg, Ca
F, Cl, Br
K, Ca, Sc
Li, Na, K
In the formula XSO4, the symbol X could represent the element
Al
Ar
Mg
Na
Which Lewis electron-dot diagram is correct for CO2?
Which electron configuration represents the electrons of an atom in an excited state?
2-2
2-2-1
2-8
2-8-1
What occurs when potassium reacts with chlorine to form potassium chloride?
Electrons are shared and the bonding is ionic.
Electrons are shared and the bonding is covalent
Electrons are transferred and the bonding is ionic.
Electrons are transferred and the bonding is covalent.
The nitrogen atoms in a molecule of N2 share a total of
A) one pair of electrons
one pair of electrons
one pair of protons
three pairs of electrons
three pairs of protons
Which formula represents a nonpolar molecule?
CH4
HCl
H2O
NH3
Which bond is most polar?
H--F
H--Cl
H--Br
H--I
What is the mass of an original 5.60-gram sample of iron-53 that remains unchanged after 25.53 minutes?
0.35
0.70
1.40
2.80
A rigid cylinder with a movable piston contains a sample of gas. At 300. K, this sample has a pressure of 240. kilopascals and a volume of 70.0 milliliters. What is the volume of this sample when the temperature is changed to 150. K and the pressure is changed to 160. kilopascals?
35.0 mL
52.5 mL
70.0 mL
105 mL
A compound has the empirical formula CH2O and a gram-formula mass of 60. grams per mole. What is the molecular formula of this compound?
CH2OB) C2H4O2C) C3H8OD) C4H8O4
C2H4O2
C3H8O
C4H8O4
What is the gram-formula mass of (NH4)3PO4?
112
121
149
242
What is the number of moles of CO2 in a 220.-gram sample of CO2 (gram-formula mass = 44 g/mol)?
0.20 mol
5.0 mol
15 mol
44 mol
Given the equation representing a chemical reaction:
NaCl(aq) + AgNO3(aq) NaNO3(aq) + AgCl(s)
This reaction is classified as a
Synthesis
Decomposition
Single Replacement
Double Replacement
Given the unbalanced equation above, what is the coefficient of O2 when the equation is balanced correctly using the smallest whole number coefficients?
1
2
3
4
Given the balanced equation for the reaction of butane and oxygen:
2C4H10 + 13O2 8CO2 + 10H2O + energy
How many moles of carbon dioxide are produced when 5.0 moles of butane react completely?
5
10
20
40
For a given chemical reaction, the addition of a catalyst provides a different reaction pathway that
decreases the reaction rate and has a higher activation energy
decreases the reaction rate and has a lower activation energy
increases the reaction rate and has a higher activation energy
increases the reaction rate and has a lower activation energy
A
B
C
D