Question

Please show explanations/formula used. Thank you!

1. Acetylene gas has a molar formula of C2H2. What is the pressure in atmospheres if 52 grams of the gas is at a temperature of 20.0° C and contained within a volume of 4L? [C is 12g/mol; H is 0g/mol]

Answer 1

Answer 2

Given:

• Mass of acetylene (${\text{C}}_2{\text{H}}_2$) = 52 g

• Volume ($V$) = 41 L

• Temperature ($T$) = 20.0°C

• Molar masses:

• Carbon ($\text{C}$) = 12 g/mol

• Hydrogen ($\text{H}$) = 1 g/mol (Note: Corrected from "0 g/mol" in the question, likely a typo)

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Step 1: Calculate Molar Mass of Acetylene

$${\text{Molar mass of C}}_2{\text{H}}_2=(2\times 12\text{g/mol})+(2\times 1\text{g/mol})=26\text{g/mol}$$

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Step 2: Determine Moles of Acetylene

$$n=\frac{\text{mass}}{\text{molar mass}}=\frac{52\text{g}}{26\text{g/mol}}=2\text{moles}$$

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Step 3: Convert Temperature to Kelvin

$$T=20.0\mathrm{°}C+273.15=293.15\text{K}$$

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Step 4: Apply the Ideal Gas Law

$$PV=nRT⟹P=\frac{nRT}{V}$$

Where:

• $R$ (gas constant) = 0.0821 L·atm·K⁻¹·mol⁻¹

• $n$ = 2 moles

• $V$ = 41 L

• $T$ = 293.15 K

$$P=$$$$P=\frac{48.11}{41}=1.173\text{atm}$$

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Answer:

The pressure of the acetylene gas is 1.17 atm  .