Photo AI

An analysis is carried out on a sample of unknown gas - VCE - SSCE Chemistry - Question 14 - 2011 - Paper 1

Question icon

Question 14

An-analysis-is-carried-out-on-a-sample-of-unknown-gas-VCE-SSCE Chemistry-Question 14-2011-Paper 1.png

An analysis is carried out on a sample of unknown gas. The density of the gas is 2.86 grams per litre at STP. The molecular formula of the gas is A. HCl B. Cl₂ C. NO... show full transcript

Worked Solution & Example Answer:An analysis is carried out on a sample of unknown gas - VCE - SSCE Chemistry - Question 14 - 2011 - Paper 1

Step 1

Calculate the Molar Mass using Density

96%

114 rated

Answer

To determine the molecular formula of the gas, we first need to calculate the molar mass using the formula:

molar mass=density×RTPmolar\,mass = density \times \frac{RT}{P}

Where:

  • Density = 2.86 grams per litre
  • At STP, R (ideal gas constant) = 0.0821 L·atm/(K·mol)
  • T (temperature) = 273.15 K
  • P (pressure) = 1 atm

Substituting the values:

molar mass=2.86×0.0821×273.151≈63.3 g/molmolar\,mass = 2.86 \times \frac{0.0821 \times 273.15}{1} \approx 63.3 \text{ g/mol}

Step 2

Determine the Molecular Formula based on Molar Mass

99%

104 rated

Answer

Now, we have a calculated molar mass of approximately 63.3 g/mol.

Next, we need to compare this value with the molar masses of the given compounds:

  • HCl = 36.5 g/mol
  • Cl₂ = 70.9 g/mol
  • NO₂ = 46.0 g/mol
  • SO₂ = 64.1 g/mol

The closest match to our calculated molar mass is SO₂ (64.1 g/mol).

Therefore, the molecular formula of the gas is D. SO₂.

Join the SSCE students using SimpleStudy...

97% of Students

Report Improved Results

98% of Students

Recommend to friends

100,000+

Students Supported

1 Million+

Questions answered

;