Chemistry 110 - 02
Winter 2017
Eighth Homework



Study Hill and McCreary Chapter 6 sections 1 - 5.
Begin to study Hill and McCreary Chapter 7 sections 1, 2, and 4 - 6.
Prepare for the next lab and write the lab report.
The sixth quiz will include questions from the topics below. To be prepared for the quiz, you should
be able to answer these questions using only the periodic table you received in class and the
information given. Any quiz may include questions about lab safety and procedures.
Due 7:30 am Wednesday, February 22. 10 Points.
Late homework is not accepted after 8:30 am Thursday, February 23.
1. Perform the following calculations.
a. What is the mass in grams of 0.392 moles magnesium hydroxide?
b. How many moles is 34.8 g H2SO4?
2. Write the formula for each of these compounds.
a. calcium fluoride
b. lithium phosphide
d. potassium chlorate
e. ammonia
c. magnesium nitride
f. sodium bicarbonate
3. Give the chemical formula for each of the following compounds.
a. potassium sulfide
b. ammonium sulfate
c. calcium phosphate
d. aluminum nitrate
e. magnesium hydroxide
f. lithium acetate
4. Classify each of these compounds as molecular or ionic.
a. CaF2
b. NH3
c. NH4Cl
d. HCl
5. Anne is working in the lab. She has a bottle labeled “0.100 M NaCl(aq)”. Complete the
sentences.
a. In this solution, NaCl is the ____________________.
b. In this solution, water is the ____________________.
c. Anne pours half the liquid from the bottle into a beaker. The concentration of the solution
that is left in the bottle is ___________________.
d. Now Anne adds 100 mL of water to the solution in the beaker and stirs the solution. The new
solution is more _________________ than the original.
6. You have a 0.677 M KNO3(aq) solution.
a. What is the solute?
b. What is the solvent?
c. How many moles of KNO3 are in 55.0 mL of the solution?
7. You have a 0.148 M NH3(aq) solution.
a. “mL” is the symbol for “milliliter”. “M” is the symbol for __________________.
b. How many mL of the solution contains 0.0733 moles of NH3?
Page 1 of 2
8. You have a 0.385 M sodium chloride solution.
a. What volume of the solution in mL contains 0.123 moles of sodium chloride?
b. How many moles of sodium chloride is in 135 mL of the solution?
9. Some KBr dissolves in water. Sketch how the ions and the water molecules are arranged in
this solution. (I recommend you run the Dissolving Salt in Water simulation.) Show only one
KBr, but show many H2O.
10. Each of these compounds is dissolved in water. What nanoscale particles (atoms, molecules,
ions) are mixed with the water molecules in each solution?
a. NaCl
b. CH3OH
c. KOH
d. Na2SO4
11. Which of these soluble compounds are electrolytes?
a. NaCl
b. CH3OH
c. KOH
d. Na2SO4
12. In the early 19th century, Faraday discovered electrolytes. He found that when an electrolyte is
dissolved in water, the solution ___________________.
13. In the early 20th century, Arrhenius won a Nobel Prize in Chemistry for discovering that
electrolyte solutions contain ____________________.
14. Draw a picture of what each of these looks like at the nanoscale.
a. Ice
b. liquid water
c. water after it evaporates
d. water after it boils
15. Give the name for each of these physical changes.
a. A solid turns to a liquid.
b. A solid turns to gas without becoming a liquid.
c. A liquid turns to gas.
d. A gas turns to solid without becoming a liquid.
16. a. Is energy required (absorbed) or released when a liquid evaporates?
b. What is this energy called?
17. Which one of these has the strongest London dispersion attractions in the pure element?
He, Ne, Ar, or Kr
18. For each pair of molecules, indicate which has the stronger London dispersion attraction.
a. CH4 or CH3CH2CH3
b. CH4 or CCl4
19. The bond energy is the amount of energy needed to break the bond. A C-C single
bond has a bond energy of 347 kJ/mole. This means it takes 348 kJ of energy to
break one mole of C-C single bonds. The bond energy of a C=C double bond is 611
kJ/mole. This means that it takes 611 kJ/mole of energy to break both bonds in the
double bond.
a. How much energy does it take to break only the second bond in a C=C double
bond so that it ends with a C-C single bond? The bond energy of the double bond
(611 kJ/mole) is the sum of the bond energy of the single bond (347 kJ/mole) and
the bond energy of the second bond in the double bond.
b. How does the energy needed to break only the second bond compare to the energy needed to
break a C-C single bond?
Page 2 of 2