Name: ________________________________ Period ____ Unit 07: States of Matter Practice Test

 

Problems: You must show all your work beginning with one of the equations:

 

Rate A = √ molar mass B                     P1V1 = P2V2                             V1/T1 = V2/T2

Rate B     √ molar mass A

P1V1/T1 = P2V2/T2                    PV = nRT        R=0.0821 L·atm/mole·K

 

Solve for the unknown variable before entering any numbers or units. Make sure you have units after all numbers that require them, use proper significant figures in your answer and circle your answer.

 

 

1. If H2 has an effusion rate of 0.00119 moles/s. What would the effusion rate for NH3 be in moles/s?

 

 

 

 

 

 

 

 

 

 

 

 

2. What would be the molar mass of the compound that would effuse at a rate equal to 189% of the rate of COCl2?

 

 

 

 

 

 

 

 

 

 

 

 

3. A gas system has an initial volume of 7.79 L with the pressure unknown. When the volume changes to 6.66 L with constant temperature, the pressure is found to be 7.04 atm. What was the initial pressure in atm?

 

 

 

 

 

 

 

 

 

 

4. A gas system has an initial pressure of 1730 torr with the volume unknown. When the pressure changes to 6400 torr with constant temperature, the volume is found to be 0.872 L. What was the initial volume in L?

 

 

 

 

 

 

 

 

 

5. A gas system has initial volume and temperature of 6.51 L and 292.1 K. If the temperature changes to 18.60 K, with constant pressure, what will the resultant volume be in mL?

 

 

 

 

 

 

 

 

 

6. A gas system has an initial volume of 7.33 L with the temperature unknown. When the volume changes to 2.95 L with constant pressure, the temperature is found to be 157.0 K. What was the initial temperature in oC?

 

 

 

 

 

 

 

 

 

7. A closed gas system initially has volume and temperature of 3.25 L and 1243 oC with the pressure unknown. If the same closed system has values of 1080 torr, 1010 mL and 416 K, what was the initial pressure in atm?

 

 

 

 

 

 

 

 

 

8. A closed gas system initially has pressure and temperature of 889 torr and 671 K with the volume unknown. If the same closed system has values of 1.56 atm, 2.47 L and 737 K, what was the initial volume in L?

 

 

 

 

 

 

9. A gas system has pressure, volume and amount of 0.396 atm, 2.07 L and 0.0456 moles, respectively. What is the temperature in K?

 

 

 

 

 

 

 

 

 

10. A gas system has pressure, amount and temperature of 1250 torr, 0.271 moles and 375 K, respectively. What is the volume in mL?

 

 

 

 

 

 

 

 

 

11. In an experiment 2.78 grams of a gas are collected and found to have a volume of 1.63 liters at a temperature of 35.0oC and a pressure of 1.134atm.  Identify this Elemental gas.

 

 

 

 

 

 

 

 

 

12. Calculate the number of 20.0 liter tanks of Hydrogen gas at 20.0oC and 15.0 atm which would have been required to fill the German airship, the Hindenberg.  The volume of the Hindenberg was about 2.50 x 107 liters at 1.10 atm and 20.0oC.  Ignore the fact that some hydrogen remains in the tank when it is "empty", i.e. pretend the tank becomes completely empty.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Use the Average Bond Enthalpy table to determine the enthalpy change of each reaction.

 

Single Bonds (gaseous molecules) (kJ/mole)
C−H    413                  N−H    391                  O−H    463                  F−F     155

C−C    348                  N−N    163                  O−O    146                             

C−N    293                  N−O    201                  O−F     190                  Cl−F    253

C−O    358                  N−F     272                  O−Cl   203                  Cl−Cl  242

C−F     485                  N−Cl   200                  O−I     234                             

C−Cl   328                  N−Br   243                                                      Br−F    237

C−Br   276                                                      S−H     339                  Br−Cl  218

C−I      240                  H−H    436                  S−F     327                  Br−Br  193

C−S     259                  H−F     567                  S−Cl    253                             

                                    H−Cl   431                  S−Br    218                  I−Cl     208

Si−H    323                  H−Br   366                  S−S     266                  I−Br    175

Si−Si   226                  H−I     299                                                      I−I       151

Si−C    301

Si−O    368

Si−Cl   464

 

Multiple Bonds (gaseous molecules) (kJ/mole)

C=C    614                  N=N    418                  O=O    495

C≡C    839                  N≡N    941                 

C=N    615                  N=O    607                  S=O     523

C≡N    891                                                      S=S     418

C=O    799                 

C≡O    1072               

 

13) a) Write and balance the combustion reaction of ethyne gas (CHCH):

 

 

 

b) Draw a sketch of all of the molecules involved in the above reaction.

 

 

 

c) Determine the enthalpy change of the reaction. Show all of your work! Remember that you have to add energy to break a bond (positive) and you get energy back when a new bond is formed (negative).

 

 

 

 

 

 

 

d) Is the reaction endothermic or exothermic?