You must be able to do the following to achieve mastery:
Standard 5.1
o Understand all of the terms from the worksheet “Solution Vocabulary”.
o
Perform calculations involving percent by mass
Example 1: A sample of salt water contains 5.00% NaCl by mass. If the solution has a mass of
250 grams, how many grams of NaCl are in the solution?
o
Perform calculations involving molarity
Example 2: How many grams of AgNO3 are needed to make 470 mL of 0.250 M AgNO3?
Example 3: How many mL of 1.30 M CaCl2 can be made using 50.0 grams of CaCl2?
o
Carry out a titration to determine the concentration of an unknown solution.
Titration procedure:
1) Place a specific amount of titrate in a beaker or flask
2) Pour titrant with a known concentration in the biuret
3) Add indicator to the titrate
4) Add titrant from the biuret to the titrate until the endpoint is reached
5) Calculate moles of titrant using volume and molarity
6) Calculate moles of titrate using stoichiometry
7) Calculate molarity of titrate using moles and volume
o
Determine concentration of an unknown solution from titration data (steps 5-7 above)
Example 4: Determine the molarity of NaOH if 12.7 mL of .500 M H2SO4 are needed to titrate a
25.0 mL sample of the NaOH.
H2SO4 + 2 NaOH  2 H2O + Na2SO4
o
Perform titration calculations involving a solution that has been diluted prior to titration.
Example 5: A 20.00 mL sample of a solution of hydrofluoric acid is diluted to 500.00 mL. A
25.00 mL sample of the diluted solution requires 15.83 mL of a 0.1500 M NaOH solution to be
titrated to the equivalence point. What is the molarity of the original HF solution?
HF + NaOH  H2O + NaF
Standard 5.2
o Solve problems involving the ideal gas law (PV = nRT)
Example 6: Given that 193 grams of carbon monoxide gas, CO, are present in a container of
volume 30.4 L, what is the pressure of the gas if the temperature is 19.0oC?
Example 7: At what temperature, in oC, will 9.8 moles of SF6 gas occupy a volume of 100 L if
the pressure of the gas is 952 kPa?
o
Solve problems using the ideal gas law when one or more of the conditions change.
Example 8: A balloon with a volume of 2.50 L at 1.2 atm and 20oC is allowed to rise to the
stratosphere where the temperature and pressure are -23oC and 0.00300 atm respectively.
Calculate the final volume of the balloon.
Example 9: The temperature of a gas initially at STP is raised to 210oC while the volume is kept
constant. Calculate the final pressure of the gas.
Standard 5.3
o Solve basic stoichiometry problems involving gases.
Example 10: How many liters of oxygen are produced at STP when 2.50 g of hydrogen peroxide,
H2O2, decomposes?
2H2O2(aq) → 2H2O(l) + O2(g)
Example 11: If 15.0 moles of ethane, C2H6, react with oxygen, what is the volume of CO2, in
liters, produced at 23.0oC and 0.985 atm?
2 C2H6(g) + 7 O2(g)  4 CO2(g) + 6 H2O(l)
Example 12: If 9.0 L of O2 reacts with excess nitrogen monoxide at 31oC and 1.5 atm, how many
grams of NO2 are produced?
2 NO(g) + O2(g)  2 NO2(g)
Answers to example problems:
1. 12.5 g NaCl
2. 20.0 g AgNO3
3. 34.7 mL
4. 0.508 M NaOH
5. 2.37 M HF
6. 5.43 atm
7. 895oC
8. 853 L
9. 1.77 atm
10. 0.823 L O2
11. 740 L
12. 49.8 g