Myrecene is a naturally occurring compound found in the leaves of bay trees - VCE - SSCE Chemistry - Question 4 - 2009 - Paper 1

To calculate the amount of hydrogen gas reacting, we can use the ideal gas law:

$n = \frac{PV}{RT}$

Where:

• P = pressure = 105.0 kPa
• V = volume = 510 mL = 0.510 L
• R = universal gas constant = 8.31 J/(mol·K)
• T = temperature in Kelvin = 20.0 + 273 = 293 K

Substituting the values,

$n = \frac{105.0 \times 0.510}{8.31 \times 293} = 0.0220 \text{ mol}$

To find the mass of C10H22 produced, we can use the molar mass of C10H22. First, we calculate the moles produced, which is equal to the moles of hydrogen reacting:

• Moles of C10H22 = 0.0220 mol

The molar mass of C10H22 is:

• C: 12.01 g/mol × 10 = 120.1 g/mol
• H: 1.008 g/mol × 22 = 22.176 g/mol
• Molar mass of C10H22 = 120.1 + 22.176 = 142.276 g/mol

Thus, the mass produced is: $mass = moles \times molar \ mass = 0.0220 \times 142.276 = 3.14 \text{ g}$

Each molecule of myrecene has 3 double bonds. This can be deduced by analyzing the structure of myrecene and considering that during the hydrogenation process, these double bonds are converted to single bonds, leading to the formation of a saturated hydrocarbon.