Question

A 5.73 L flask at 25°C contains 0.0388 mol of N2, 0.147 mol of CO, and 0.0803 mol of H2. What is the total pressure in the flask in atmospheres?

Answer 1

Boyle’s Law and the Ideal Gas Law tell us the total pressure of a mixture depends solely on the number of moles of gas, and not the kinds of molecules. Boundless Chemistry

Calculate the total mole of gas.

Total mole of gas = 0.0388 mol + 0.147 mol + 0.0803 mol = 0.2661 mol

Use the ideal gas law to calculate total pressure.

PV = nRT, where;

P = pressure = ?

V = volume = 5.73 L

n = mole = 0.2661 mol

R = gas constant = 0.082057 L·atm·K^-1·mol^-1

T = temperature = 25°C + 273.15 = 298 K (Temperature must be in Kelvins for gas laws.)

Rearrange the formula to isolate P. Insert known values and solve.

P = nRT/V

P = [(0.2661 mol)·(0.082057 L·atm·K^-1·mol^-1)·(298 K)]/5.73 L = 1.14 atm to three significant figures

The total pressure in the flask is ~1.14 atm.

Answer 2

The total pressure in the flask is approximately 1.14 atm (3 s.f.).

Step-by-step explanation:

To find the total pressure in the flask in atmospheres, we can use the ideal gas law.

Ideal Gas Law

`\boxed{\sf PV=nRT}`

where:

• P is the pressure measured in atmospheres (atm).
• V is the volume measured in liters (L).
• n is the number of moles.
• R is the ideal gas constant (0.08206 L atm mol⁻¹ K⁻¹).
• T is the temperature measured in kelvin (K).

First, calculate the total number of moles of gas in the flask:

`\begin{aligned}\sf n_(total) &= \sf n(N_2) + n(CO) + n(H_2)\\&= \sf 0.0388 \; mol + 0.147\; mol + 0.0803\;mol\\&= \sf 0.2661\;mol\end{aligned}`

Next, convert the temperature from Celsius to kelvin by adding 273.15:

`\implies \sf T = 25^(\circ)C + 273.15 = 298.15\;K`

Therefore:

• V = 5.73 L
• n = 0.2661 mol
• R = 0.08206 L atm mol⁻¹ K⁻¹
• T = 298.15 K

Substitute the values into the formula and solve for P:

`\implies \sf P \cdot 5.73=0.2661 \cdot 0.08206 \cdot 298.15`

`\implies \sf P=(0.2661 \cdot 0.08206 \cdot 298.15)/(5.73)`

`\implies \sf P=1.13620469...`

`\implies \sf P=1.14\;atm\;(3\;s.f.)`

Therefore, the total pressure in the flask is approximately 1.14 atm (3 s.f.).