Ch. 9 & 13 stochiometry & gas                                   test                   70 points                                  chemistry

Show your work in an organized manner, include (i) any relevant equation (or formula), (ii) conversion factor(s), (iii) put the proper units in your calculations and answer, and (iv) have the proper number of significant figures in your answer.

Academic Honesty:   The answers on this test are my own and I am using only the allowed set of notes as described in the syllabus.  I have not discussed the test questions with anyone before or during the test nor have I seen the test questions prior to the exam.  If you violate any of the preceding items or do not sign, your semester grade is a F.

                                                                                                Signature:  ___________________

1. A sealed syringe has a pressure of 95 kPa, volume of 45 mL, and temperature of 22 ºC.  The syringe’s volume is reduced to 15 mL and its temperature reduced to -5.0 ºC; what is the pressure in the syringe ?  [10 points]

2.  A rigid container at 325 K has a pressure of 95 kPa and contains 8.0 g hydrogen gas, 16 g helium gas, and 80. g argon.  [15 points]

a.  What is the partial pressure of argon in the container ?

b.  what is the volume of the container ?

3. In regards to the reaction:  2.0 L N2(g)  +  5.0 L H2(g)  →  NH3(g)  at STP,  [20 points]

a. Write the balanced chemical equation using the lowest ratio of integers

b. Determine the number of moles of nitrogen and hydrogen gas at the beginning of the reaction.

c.  Identify / justify the limiting reactant

d.  Determine the number of grams of NH3 produced in the reaction

4.  In the combustion of 5.0  g ethane, C2H6, and 10.0 g oxygen gas, how much water was produced in the reaction ?  Don’t need to determine the amount of carbon dioxide in the reaction.   [15 points]

5.  5.0 g hydrogen gas reacts with excess nitrogen gas to form ammonia, NH3.  If the percent yield in the reaction is 88%, how many grams of ammonia was produced in the reaction ?  [10 points]