Name: _____________________ date: __________________ period: _______

Ch. 13 gas **test** 60 points (5 ec) chemistry

In problems involving any calculation, 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.

1. Solve [10 points]

a. 575 torr = __ kPa

b. 225 kPa = __ atm

2. A 45 mL syringe at 21 ºC has a pressure of 95 kPa. The temperature of the syringe was reduced to 5**.**0 ºC and its volume was decreased to 15**.**0 mL; what is the pressure in the syringe ? [10 points]

3. A 35 mL syringe has a pressure of 745 torr and has 3**.**5 millimole of helium; what is the temperature in the syringe ? [10 points]

4. A 5**.**0 L container has 4**.**0 grams of He, 21**.**0 grams of N2 gas, and 56**.**0 grams of O2 gas at 325** **K. [15 points]

a. What is the partial pressure of oxygen ?

b. What is the mole fraction of oxygen ?

- What is the total pressure ?

- Excess aqueous hydrogen chloride reacts with magnesium, which produces 35 mL of a gas at 22
**.**0 ºC and the atmospheric pressure is 755 torr and the height of the liquid in the eudiometer tube was 25 cm higher than the level of water in the pneumatic trough. What is the mass of magnesium based on the preceding information ? [hint: 10**.**3 m of water = 760 torr; 20 points]