Question

QUESTION 1 A sample of nitrogen gas is sealed into a 18.6 L container at 715.2 torr and 146.8 °C. How many nitrogen molecules are in the container? (Enter your value in E-notation with three significant figures.] QUESTION 2 A sample of carbon monoxide gas occupies a volume of 200 mL at a pressure of 551.9 torr and a temperature of 633 K. What would its temperature be if the volume were changed to 84 mL at a pressure of 539.8 torr? QUESTION 3 Consider the reaction between hydrogen gas and oxygen gas to form water: 2 H2(g) + O2(g) + 2 H2O(g). How many grams of water could be produced by the reaction of 4.7 liters of hydrogen with 4.11 liters of oxygen at STP? (Hint: check for limiting reagent). QUESTION 4 Automobile airbags use the decomposition of sodium azide, NaN3, to provide gas for rapid inflation: 2 NaN3(s) + 2 Na(s) + 3 N2(g). Using stoichiometry and the ideal gas law, calculate the mass (in g) of NaNg required to provide 24 L of N2(g) at 25.8 °C and 1.00 atm?

Answer 1

1)

Given:

P = 715.2 torr

= (715.2/760) atm

= 0.9411 atm

V = 18.6 L

T = 146.8 oC

= (146.8+273) K

= 419.8 K

find number of moles using:

P * V = n*R*T

0.9411 atm * 18.6 L = n * 0.08206 atm.L/mol.K * 419.8 K

n = 0.5081 mol

use:

number of molecules = number of mol * Avogadro’s number

number of molecules = 0.5081 * 6.022*10^23 molecules

number of molecules = 3.06*10^23 molecules

Answer: 3.06E23 molecules

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