A mixture contains several different organic liquids all of which boil at temperatures greater than 50°C. The compounds present in the mixture are separated. Three of the compounds, compounds X, Y and Z, are analysed as follows. Compound X is vaporised. At a temperature of 120°C and a pressure of 115 kPa, a 0.376 g sample of the vapour occupies 124 mL. a. Calculate the molar mass, in g mol⁻¹, of compound X. Compound Y is an alkanol of molecular formula C4H10O. b. i. In the boxes below, draw the structural formulas, showing all bonds, of the four possible alkanols with a molecular formula of C4H10O.

SSCE VCE Chemistry Components of Mixtures: A mixture contains several diffe

A mixture contains several different organic liquids all of which boil at temperatures greater than 50°C - VCE - SSCE Chemistry - Question 4 - 2008 - Paper 1

Question 4

A mixture contains several different organic liquids all of which boil at temperatures greater than 50°C. The compounds present in the mixture are separated. Three o... show full transcript

Worked Solution & Example Answer:A mixture contains several different organic liquids all of which boil at temperatures greater than 50°C - VCE - SSCE Chemistry - Question 4 - 2008 - Paper 1

Step 1

Calculate the molar mass, in g mol⁻¹, of compound X.

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Answer

To determine the molar mass of compound X, we will use the Ideal Gas Law, rearranged to find molar mass.

Find the number of moles (n) using the formula: $n = \frac{PV}{RT}$ Where:
- $P = 115$ kPa
- $V = 124$ mL = 0.124 L
- $R = 8.314 \: J \: mol^{-1} \: K^{-1}$ (which can be converted to kPa L by using the equivalent constant: $R = 8.314 \: kPa \: L \: mol^{-1} \: K^{-1}$ )
- $T = 120°C = 393 K$
Therefore: $n = \frac{115 \times 0.124}{8.314 \times 393} = 0.00437 \: mol$
Calculate the molar mass (M) using the formula: $M = \frac{m}{n}$
Where:
- $m = 0.376 g$
Thus: $M = \frac{0.376}{0.00437} = 86.1 \: g \: mol^{-1}$

This indicates that the molar mass of compound X is 86.1 g/mol.

Step 2

In the boxes below, draw the structural formulas, showing all bonds, of the four possible alkanols with a molecular formula of C4H10O.

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Answer

The four possible alkanols with the molecular formula C4H10O are:

Methyl-1-propan-1-ol:
Methyl-1-propan-2-ol:
2-Methyl-1-propan-1-ol:
2-Methyl-1-propan-2-ol:

In each structural formula, all bonds should be clearly indicated, including the hydroxyl (-OH) group.

A mixture contains several different organic liquids all of which boil at temperatures greater than 50°C - VCE - SSCE Chemistry - Question 4 - 2008 - Paper 1

Worked Solution & Example Answer:A mixture contains several different organic liquids all of which boil at temperatures greater than 50°C - VCE - SSCE Chemistry - Question 4 - 2008 - Paper 1

Calculate the molar mass, in g mol⁻¹, of compound X.

In the boxes below, draw the structural formulas, showing all bonds, of the four possible alkanols with a molecular formula of C4H10O.

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