Answer:
1) The temperature of the balloon is 194.5 K = -78.65 °C
2) The pressure inside the chamber is 0.684 atm
3) The partial pressure of O2 is 157.3 mmHg
Step-by-step explanation:
A weather balloon is filled with 25 grams of nitrogen (N2) gas at a pressure of 9.5 atm and a volume of 1500 ml. What is the temperature of the balloon?
Step 1: Data given
Mass of N2 : 25.0 grams
Pressure = 9.5 atm
Volume = 1500 mL = 1.5 L
Molar mass of N2 = 28.0 g/mol
Step 2: Calculate moles N2
Moles N2 = mass / molar mass
Moles N2 = 25.0 grams / 28.0 g/mol
Moles N2 = 0.893 moles
Step 3: Calculate temperature
p*V = n*R*T
T = (p*V)/(n*R)
⇒ with T =the temperature of the balloon = TO BE DETERMINED
⇒ with p = the pressure in the balloon = 9.5 atm
⇒ with V = the volume of the gas = 1.5 L
⇒ with n = the moles of N2 = 0.893 moles
⇒ with R = the gas constant = 0.08206 L*atm/mol*K
T = (9.5 * 1.5)/(0.893*0.08206)
T= 194.5 K = -78.65 °C
The temperature of the balloon is 194.5 K = -78.65 °C
2) A researcher pumps 0.0128 moles of nitrogen (N2) into a 450 ml chamber held at 20 oC. What is the pressure inside the chamber?
Step 1: Data given
Moles of N2 = 0.0128 moles
Volume = 450 mL = 0.450 L
Temperature = 20.0 °C
Step 2: Calculate pressure
p*V = n*R*T
p = (n*R*T)/V
⇒ with T =the temperature in the chamber = 20.0 °C = 293.15 K
⇒ with p = the pressure in the chamber = TO BE DETERMINED
⇒ with V = the volume of the gas = 0.450 L
⇒ with n = the moles of N2 = 0.0128 moles
⇒ with R = the gas constant = 0.08206 L*atm/mol*K
p = (0.0128*0.08206*293.15)/0.450
p = 0.684 atm
The pressure inside the chamber is 0.684 atm
The atmosphere is about 21% oxygen. At a pressure of 749 torr, what is the partial pressure of O2?
Step 1: Data given
Pressure = 749 torr
% O2 = 21%
Step 2: Calculate partial pressure of O2
p(atmospheric) = p(O2) + p(N2) + other gasses
p(atmospheric) = 749 torr
p(O2) = 0.21 * 749 mmHg
p(O2) = 157.3 mmHg
The partial pressure of O2 is 157.3 mmHg