Question

A 50.0 mL sample of a gas was found to have a pressure of l.0 atm at 25 degree C. What will be the new volume if the temperature is changed to 50 degree C at constant pressure? A 2.00 L sample of Nitrogen gas at 25.0 degree C was found to have a pressure of 1.00 atm. How many moles of gas are present and what is the mass of the gas in grams? The total pressure in a mixture of Nitrogen and chlorine gas was found to be 1.65 atm. if the partial pressure of Nitrogen was 0.65 atm, what is the partial pressure of Chlorine gas. Octane, C_8H_18, is a flammable hydrocarbon. It undergoes a combustion reaction (with oxygen gas) to produce Carbon dioxide and Water. Write a balanced chemical equation for this reaction How many mole of oxygen is consumed if 0.050 mol of octane undergoes Combustion?

Answer 1

Q8.

V = 50 mL, P = 1 atm, T = 25°C = 298K

find new volume when T = 50°C = 323 K

so

V1/T1 = V2/T2

substitute

50/298 = V2/323

V2 = 323/298*50 = 51.20 mL

ii

V = 2 L of N2gas T = 298K, P = 1 atm

find moles of gas present

mol from ideal gas law

PV = nRT

n = PV/(RT)

n = (1)(2)/(0.082*298) = 0.08184645 moles of gas

mass = mol*MW

MNW of N2 = 28 g/mol

mass = mol*MW = (0.08184645*28) = 2.2917006 g of N2