SSCE VCE Chemistry Carbon-Based Fuels: What mass of butane (M = 58.0 g

What mass of butane (M = 58.0 g mol⁻¹) must undergo complete combustion to raise the temperature of 100.0 g of water by 1.00 °C? Assume that there is no heat loss. - VCE - SSCE Chemistry - Question 8 - 2011 - Paper 1

Question 8

What mass of butane (M = 58.0 g mol⁻¹) must undergo complete combustion to raise the temperature of 100.0 g of water by 1.00 °C? Assume that there is no heat loss.

Worked Solution & Example Answer:What mass of butane (M = 58.0 g mol⁻¹) must undergo complete combustion to raise the temperature of 100.0 g of water by 1.00 °C? Assume that there is no heat loss. - VCE - SSCE Chemistry - Question 8 - 2011 - Paper 1

Step 1

Calculate the amount of heat needed to raise the temperature of the water.

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Answer

The heat required (q) to raise the temperature of the water can be calculated using the formula:

$q = m imes c imes riangle T$

where:

$m$ is the mass of water (100.0 g)
$c$ is the specific heat capacity of water (4.18 J g⁻¹ °C⁻¹)
$\triangle T$ is the change in temperature (1.00 °C)

Substituting the values:

$q = 100.0 ext{ g} imes 4.18 ext{ J g⁻¹ °C⁻¹} imes 1.00 ext{ °C} = 418 ext{ J}$

Step 2

Determine the heat released per mole of butane combusted.

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Answer

The standard heat of combustion for butane is approximately -2877 kJ/mol. Converting this value to joules:

-2877 kJ/mol = -2877000 J/mol.

Therefore, the heat released by combusting one mole of butane is 2877000 J.

Step 3

Calculate the number of moles of butane required to release the necessary heat.

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Answer

To find the moles of butane (n) needed to generate 418 J, use the formula:

$n = \frac{q}{\Delta H_{combustion}}$

Substituting the values:

$n = \frac{418 ext{ J}}{2877000 ext{ J/mol}} \approx 0.000145 ext{ mol}$

Step 4

Calculate the mass of butane required using its molar mass.

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Answer

Using the molar mass of butane (M = 58.0 g/mol), the mass of butane (m) can be calculated as:

$m = n \times M$

Substituting the values:

$m = 0.000145 ext{ mol} \times 58.0 ext{ g/mol} \approx 0.00841 ext{ g}$

This is approximately 8.44 g, making the correct answer:

D. 8.44 x 10³ g

What mass of butane (M = 58.0 g mol⁻¹) must undergo complete combustion to raise the temperature of 100.0 g of water by 1.00 °C? Assume that there is no heat loss. - VCE - SSCE Chemistry - Question 8 - 2011 - Paper 1

Worked Solution & Example Answer:What mass of butane (M = 58.0 g mol⁻¹) must undergo complete combustion to raise the temperature of 100.0 g of water by 1.00 °C? Assume that there is no heat loss. - VCE - SSCE Chemistry - Question 8 - 2011 - Paper 1

Calculate the amount of heat needed to raise the temperature of the water.

Determine the heat released per mole of butane combusted.

Calculate the number of moles of butane required to release the necessary heat.

Calculate the mass of butane required using its molar mass.

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