CHM 113 FINAL STUDY GUIDE
QUESTIONS & ANSWERS CORRECT
100%
What is the meaning of the term equivalent weight? - ANSWER-the mass of a
particular substance that can combine with or displace one gram of hydrogen or
eight grams of oxygen
-that weight of the substance which will react with or produce one mole of hydrogen
What safety rule do we "bend" in this lab? - ANSWERwe are breaking the rule of
adding water to an acid
What would happen if the Mg ribbon were left out and a layer of magnesium oxide
formed on it and was not rubbed off with the steel wool? What would happen to your
results? Explain. - ANSWERIf the Mg ribbon were left out then it would react with the
O2 in the air forming MgO which does not react with HCl the way we want. Our
results would not reflect what we want to happen
Using the appropriate conversion factors convert 95.3 mm H2O to torr. -
ANSWER95.3/13.59 = 7 torr
How would your value for equivalence weight be affected if some of the H2 gas
produced during the reaction of Mg(s) and acid escaped from the gas buret? -
ANSWERIf some of the H2 gas produced during the reaction of Mg(s) and acid
escaped from the buret, the equivalence weight would be higher
Given the following experimental values for a gas sample, find the volume of that gas
sample under standard temperature and pressure (STP) conditions. -
ANSWER(.9277)(.02608)/300.55 = x/273.15
x = 21.98 mL
Convert 711.8 torr to atm - ANSWER711.8/760.0 = 0.937 atm
What would Pw be in torr if the height of a water column in a gas buret was 21.6 cm?
- ANSWER21.6/13.6 = 1.588 torr
Why is it important to use steel wool to clean the magnesium prior to the experiment
- ANSWERit is important to use steel wool to clean the magnesium because its
removing oxidized Mg so the experiment works better
Given the activity series to the right, explain why magnesium, and not copper,
reactions with HCL - ANSWERMagnesium reacts with HCl because it is a lot more
reactive then copper. Magnesium is easily oxidized.
QUESTIONS & ANSWERS CORRECT
100%
What is the meaning of the term equivalent weight? - ANSWER-the mass of a
particular substance that can combine with or displace one gram of hydrogen or
eight grams of oxygen
-that weight of the substance which will react with or produce one mole of hydrogen
What safety rule do we "bend" in this lab? - ANSWERwe are breaking the rule of
adding water to an acid
What would happen if the Mg ribbon were left out and a layer of magnesium oxide
formed on it and was not rubbed off with the steel wool? What would happen to your
results? Explain. - ANSWERIf the Mg ribbon were left out then it would react with the
O2 in the air forming MgO which does not react with HCl the way we want. Our
results would not reflect what we want to happen
Using the appropriate conversion factors convert 95.3 mm H2O to torr. -
ANSWER95.3/13.59 = 7 torr
How would your value for equivalence weight be affected if some of the H2 gas
produced during the reaction of Mg(s) and acid escaped from the gas buret? -
ANSWERIf some of the H2 gas produced during the reaction of Mg(s) and acid
escaped from the buret, the equivalence weight would be higher
Given the following experimental values for a gas sample, find the volume of that gas
sample under standard temperature and pressure (STP) conditions. -
ANSWER(.9277)(.02608)/300.55 = x/273.15
x = 21.98 mL
Convert 711.8 torr to atm - ANSWER711.8/760.0 = 0.937 atm
What would Pw be in torr if the height of a water column in a gas buret was 21.6 cm?
- ANSWER21.6/13.6 = 1.588 torr
Why is it important to use steel wool to clean the magnesium prior to the experiment
- ANSWERit is important to use steel wool to clean the magnesium because its
removing oxidized Mg so the experiment works better
Given the activity series to the right, explain why magnesium, and not copper,
reactions with HCL - ANSWERMagnesium reacts with HCl because it is a lot more
reactive then copper. Magnesium is easily oxidized.
