Chem 104 Final EXAM QUESTIONS AND
VERIFIED ANSWERS GRADED A
1. A sample of aluminum contains 2.91 × 1022 atoms of aluminum.
What is the mass of this sample? [Molar mass: Al, 26.98 g/mol]: 1.30
g
2. What is the number 3,000 written in scientific notation using the
proper number of significant figures?: 3 × 10^3
3. Which statement about the modern periodic table is FALSE?:
Elements in the same period share similar chemical and physical
properties.
4. Which of the following is NOT a unit for measuring pressure?: kJ
5. A covalent bond involves which of the following?: sharing of
electrons between two atoms
6. Which statement correctly describes what is happening in the
reaction shown below?
2Mg(s) + S2(g) ’ MgS(s): Mg is oxidized.
7. Which statement explains why isotopes have different mass
numbers?: Isotopes differ in the number of neutrons each contains
,8. Enough water is added to 50.0 mL of a 0.660 M NaOH solution in
order to bring the total volume to 450.0 mL. What is the molarity of
this diluted solution?: 0.0733 M
9. The unbalanced equation for the combustion of octane, a component
of gasoline, is shown below. What would be the coefficient of carbon
dioxide once the equation is balanced?
C8H18(l) + O2(g) ’ CO2(g) + H2O(l): 16
10. When a neutral atom gains one or more electrons, what type of
particle is formed?: an anion
11. What is the name of the ionic compound with the formula Na3PO4?:
sodium phosphate
12. What law predicts the expansion of a balloon when helium is
added?: Avogadro's Law
13. Methanol (CH3OH) is the fuel used by racecars in the Indianapolis
500. It burns in the engine according to the equation below. How
many moles of oxygen gas are necessary to react completely with 12.5
L of methanol? [Density: CH3OH, 0.7910g/mL; Molar mass: CH3OH,
32.05 g/mol]
2CH3OH(l) + 3O2(g) ’ 2CO2(g) + 4H2O(g): 463 mol
14. At what temperature is a liquid converted into a gas?: the boiling
point of the liquid
, .
15. The drug "lithium" is often prescribed to treat mental illness. It is not
the element lithium, but the ionic compound Li2CO3, that is actually
administered.
What is the name of this compound?: lithium carbonateConsider the
chemical equation shown below. How many moles of oxygen gas are
needed to react with hydrogen to form one mole of water? 2H2(g) +
O2(g) ’ 2H2O(l)
16. Hydrogen fluoride will react with glass (silicon dioxide, SiO2)
according to the equation below. What mass of HF is required to
react completely with 16.0 g of glass? [Molar masses: Si, 28.09 g/mol;
F, 19.00 g/mol; H, 1.01 g/mol; O, 16.00 g/mol]
4HF(g) + SiO2(s) ’ SiF4(g) + 2H2O(g): 21.3 g
17. Two molecules of ethane experience what type of attractive forces?:
London forces
18. A solution contains the label 0.2 M KNO3. What is the correct
interpretation of this concentration?: There are 0.2 moles of KNO3 in
1 L of solution.
19. Which properly represents the Lewis structure of hydrogen sulfide,
H2S?:
VERIFIED ANSWERS GRADED A
1. A sample of aluminum contains 2.91 × 1022 atoms of aluminum.
What is the mass of this sample? [Molar mass: Al, 26.98 g/mol]: 1.30
g
2. What is the number 3,000 written in scientific notation using the
proper number of significant figures?: 3 × 10^3
3. Which statement about the modern periodic table is FALSE?:
Elements in the same period share similar chemical and physical
properties.
4. Which of the following is NOT a unit for measuring pressure?: kJ
5. A covalent bond involves which of the following?: sharing of
electrons between two atoms
6. Which statement correctly describes what is happening in the
reaction shown below?
2Mg(s) + S2(g) ’ MgS(s): Mg is oxidized.
7. Which statement explains why isotopes have different mass
numbers?: Isotopes differ in the number of neutrons each contains
,8. Enough water is added to 50.0 mL of a 0.660 M NaOH solution in
order to bring the total volume to 450.0 mL. What is the molarity of
this diluted solution?: 0.0733 M
9. The unbalanced equation for the combustion of octane, a component
of gasoline, is shown below. What would be the coefficient of carbon
dioxide once the equation is balanced?
C8H18(l) + O2(g) ’ CO2(g) + H2O(l): 16
10. When a neutral atom gains one or more electrons, what type of
particle is formed?: an anion
11. What is the name of the ionic compound with the formula Na3PO4?:
sodium phosphate
12. What law predicts the expansion of a balloon when helium is
added?: Avogadro's Law
13. Methanol (CH3OH) is the fuel used by racecars in the Indianapolis
500. It burns in the engine according to the equation below. How
many moles of oxygen gas are necessary to react completely with 12.5
L of methanol? [Density: CH3OH, 0.7910g/mL; Molar mass: CH3OH,
32.05 g/mol]
2CH3OH(l) + 3O2(g) ’ 2CO2(g) + 4H2O(g): 463 mol
14. At what temperature is a liquid converted into a gas?: the boiling
point of the liquid
, .
15. The drug "lithium" is often prescribed to treat mental illness. It is not
the element lithium, but the ionic compound Li2CO3, that is actually
administered.
What is the name of this compound?: lithium carbonateConsider the
chemical equation shown below. How many moles of oxygen gas are
needed to react with hydrogen to form one mole of water? 2H2(g) +
O2(g) ’ 2H2O(l)
16. Hydrogen fluoride will react with glass (silicon dioxide, SiO2)
according to the equation below. What mass of HF is required to
react completely with 16.0 g of glass? [Molar masses: Si, 28.09 g/mol;
F, 19.00 g/mol; H, 1.01 g/mol; O, 16.00 g/mol]
4HF(g) + SiO2(s) ’ SiF4(g) + 2H2O(g): 21.3 g
17. Two molecules of ethane experience what type of attractive forces?:
London forces
18. A solution contains the label 0.2 M KNO3. What is the correct
interpretation of this concentration?: There are 0.2 moles of KNO3 in
1 L of solution.
19. Which properly represents the Lewis structure of hydrogen sulfide,
H2S?:
