1. Molecules, Compounds, and Chemical Equations
Clicker Questions
Chapter 3
Molecules, Compounds, and Chemical Equations
Allison Soult
University of Kentucky

2. The two compounds have different formulas.
There are two compounds of Ni and O. The green colored oxide of nickel has a Ni:O mass ratio of 3.67:1 and a Ni:O atom ratio of 1:1. The black colored oxide of nickel has a Ni:O mass ratio of 2.45:1. Which of the following is correct?
The two compounds have different formulas.
The two compounds have nickel ions with different charges.
The Ni:O atom ratio of the black oxide is 2:3.
This is an example of the Law of Multiple Proportions.
All of the above are correct.
Answer: e

3. Which of the following compounds exhibits both ionic and covalent bonding?
SO2
CF4
NaCl
Na2SO4
P4O10
Answer: d

4. Which of the following would NOT be classified as a molecular compound?
NH4C2H3O2
NH3
Answer: d

5. Which of the following is the correct formula for aluminum bromide?
AlBr
Al3Br
AlBr3
Al3Br3
Answer: c

6. What is the IUPAC name for FeCl3?
iron chloride
iron trichloride
iron(III) chloride
iron chloride(III)
Answer: c

7. What is the formula for potassium carbonate?
KCO3
K(CO3)2
K2CO3
KCO6
Answer: c

8. The picture was red on sunny days and blue on rainy days.
A toy used to predict the weather had a picture containing CoCl2. It worked on the following reversible reaction: CoCl2 + 6 H2O  CoCl2 ∙ 6 H2O Which of the following statements is correct?
The picture was red on sunny days and blue on rainy days.
The picture was blue on sunny days and red on rainy days.
Answer: b

9. Which of the following correctly matches the formula with its name?
P2O5, phosphorus pentoxide
H2O, dihydrogen monoxide
NaNO3, monosodium nitrate
K2O, dipotassium monoxide
Fe2O3, iron(II) oxide
Answer: b

10. What is the name of the oxyacid formed from sulfite (SO32−)?
hydrosulfuric acid
sulfuric acid
hydrosulfurous acid
sulfurous acid
hydrogen sulfide acid
Answer: d

11. What is the molar mass of calcium phosphate?
g/mole
g/mole
g/mole
g/mole
g/mole
Answer: a

12. Which sample represents the greatest number of moles?
44.01 g CO2
1.0 moles C3H8
6.022 x 1023 molecules C4H10
18.02 g H2O
All of the samples have the same number of moles.
Answer: e

13. Which of the following contains the largest number of molecules?
10.0 g CH4
10.0 g C2H6
10.0 g SO2
10.0 g Xe
Answer: a

14. Which of the following contains the largest mass percent hydrogen?
10.0 g CH4
10.0 g C2H6
10.0 g H2O
10.0 g H2S
Answer: a

15. Calculate the number of carbon atoms in 25
Calculate the number of carbon atoms in 25.0 grams of isopropyl alcohol (C3H8O).
1.25 C atoms
15.0 C atoms
2.51 x 1023 C atoms
7.52 x 1023 C atoms
2.07 x 10–24 C atoms
Answer: d

16. An unknown compound contains the following percents by mass: C: 60
An unknown compound contains the following percents by mass: C: 60.86%, H: 5.83%, O: 23.16%, and N: 10.14%. Find the empirical formula.
C6H8O2N2
C7H8O2N
C6H8O2N
C8H8O2N
C8H8ON
Answer: b

17. What is the empirical formula of a compound containing C, H, and O if combustion of 3.69 g of the compound yields 5.40 g of CO2 and g of H2O?
CH3O
C2H3O
CHO
C2H3O2
CH2O
Answer: e

18. What are the coefficients for the decomposition of nitroglycerin?
__ C3H5N3O9  __ N2 + __ CO2 + __ H2O + __ O2
2,3,6,2,1
2,3,6,5,1
4,6,12,10,12
4,3,12,10,1
4,6,12,10,1
Answer: e

19. The mass of the reactants is equal to the mass of the products.
Which of the following statements is true about a balanced chemical reaction?
The mass of the reactants is equal to the mass of the products.
The number of each type of atom is the same in the reactants and in the products.
The moles of each type of atom is the same in the reactants and in the products.
All of the above.
Answer: d

20. Hydrocarbons are composed of just the elements carbon and hydrogen
Hydrocarbons are composed of just the elements carbon and hydrogen. Which of the following compounds has all single bonds?
naphthalene, C10H8
propane, C3H8
ethyne, C2H2
ethene, C2H4
Answer: b