REVISED EDITION
INTRODUCTORY CHEMISTRY PRACTICE PROBLEMS FOR EXAM 2 (final)
(*original problems had typos – points awarded if you find more!)
1) If 575g sample of iron starts at room temperature (20oC)and absorbs 21,000 calories, what is its final temperature?
(360)
2)What mass of solute is in 9.5L of .031M sodium nitrate? (25)
*3) If 170L of water vapor are produced by the combustion of 14g methane (CH4) at 490oC, what is the pressure
in psi? (9.5)
4)How much 0.010M KBr would be needed to make 52mL of .0025M KBr by dilution? (13)
*5) How much solid sodium hydroxide (a base) would be needed to react with 1.1L of 0.108M nitric acid (HNO3)
in a double replacement? (4.8)
*6) A solution has a pH of 3. What is the pH of a second solution if it has a hydrogen ion concentration that is
10000 times greater than the first solution? (-1)
*7) If 0.337L of hydrogen gas are produced at STP by dropping aluminum metal into hydrochloric acid solution
having a pH of 0.92, what volume of acid solution would be required? (.25)
*8) A peanut is burned and used to heat 1800g solid aluminum sample from 35oC to 60oC. How many calories
were in the peanut? (11,000)
9) If .30g calcium is reacted (replacement) with 15L of hydrochloric acid (HCl), what is the molarity of the acid?
(0.0010)
10) Find [H+] for aqueous hydrochloric acid with pH = -1.3 (20)
11) How many moles of a gas are in a 5.0L container at 20oC with a pressure of 723mm Hg? (.20)
12) How much energy is released by 325g of water at 0oC as it freezes to ice? (26000)
13) What volume of 0.0056M calcium chloride contains 12g solute? (19)
14) Find pH for solution prepared by diluting 75 mL of 6.0M NaOH with water to 100 mL (14.65)
15) What volume of fluorine gas is needed to combine with calcium to produce 157 g calcium fluoride at STP? (45)
16) A walnut is ignited and used to heat a 55g chunk of aluminum from 35oC to 60oC. If all of the walnut’s calories
went to heating the aluminum, how many calories were in the walnut? (330)
17) What volume of 0.12M nitric acid could be neutralized by 25mL of 3.0M potassium hydroxide? (625)
SUPPLEMENTAL INFORMATION
SOLUBILITY INFO
solubility in 100 mL water at 20oC
NaCl 35.7g
BaSO4 0.00023g
Mg(OH)2 0.0009g
NaOH 42g
NaNO3 92.1g
ACID INFO
ACID NAME (Ka)
acetic 1.8 x 10-5
formic 1.8 x 10-4
hydrocyanic 4.9 x 10-9
nitrous 4.6 x 10-4
ENERGY INFO Al (s) H2O (l) Fe (s)
specific heat 0.24 cal/goC 1 cal/goC 0.1082 cal/goC
heat of fusion 96 cal/g 80 cal/g 59 cal/g
heat of vaporization 2597 cal/g 540 cal/g 1492 cal/g
normal b.p. 2520oC 100oC 2862oC
normal m.p. 660oC 0oC 1536oC
GAS CONSTANT = R = 0.082 L atm/mol K (T must be in Kelvins and P must be in atm)