1. An acetylene torch undergoes the following reaction: 2 C2H2 + 5 O2  4 CO2 + 2 H2O Student “X” identified oxygen as the reducing agent. Please provide a detailed explanation (in your own words) to

1. An acetylene torch undergoes the following reaction:

2 C2H2 + 5 O2  4 CO2 + 2 H2O

Student “X” identified oxygen as the reducing agent. Please provide a detailed

explanation (in your own words) to describe whether or not the student correctly

identified the reducing agent.

2. When determining the theoretical yield for a reaction, why must we first determine which

reactant is the limiting reactant? In addition, please use your own values to provide an

example of how to determine a limiting reagent. Use the following reaction:

3 NH4NO3 (aq) + Na3PO4 (aq)  (NH4)3PO4 (aq) + 3 NaNO3 (aq)

3. Two different solutions of NaNO3 both contain 0.5 moles of NaNO3, but they have

different molarities. Please provide a detailed explanation (in your own words) how this

is possible.

4. Student “X” solved the following problem incorrectly. Please provide a detailed

explanation (in your own words) the error, or errors (there can be more than one) made

by student “X”.

Question:

                           Consider the following equation:

                                                                                 Ba(OH)2(s) + 2 HCl(aq)  BaCl2(s) + 2 H2O(l)

                                                                                  How many liters of 0.100 M HCl would be required to react

                                                                                   completely with 2.50 grams of barium hydroxide?

                                                                                    Student “X”’s response:

                                                           ? L HCl = 2.50 g Ca(OH)2 x (1 mol Ca(OH)2) x ( 1 L )

                                                                                  (154.336 g)        (0.100 mol HCl)

                                                                          =     0.16198424 L of HCl

5. What will happen to the internal pressure of a gas in a rigid container if the temperature

of the gas is increased? Will the pressure increase, decrease, or stay the same? Please

provide a detailed explanation (in your own words) using both molecular (qualitative) and

mathematical (quantitative) concepts.