Calorimetry Exam Qs

2020 Q9 ( 28% correct ans)

What is the calibration factor for this calorimeter?

• 125 J °C⁻¹

• 820 J °C⁻¹

• 847 J °C⁻¹

• 875 J °C⁻¹

2020 Q10 ( 26% correct ans)

This type of calorimeter

• has no heat loss.

• can be used for bomb calorimetry.

• requires electrical calibration in order to determine the calibration factor.

• measures energy changes that can be measured in a bomb calorimeter.

2019 Q2

The thermochemical equation for the complete combustion of glucose is

• C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O ΔH = −2860 kJ mol⁻¹

• C₆H₁₂O₆ + 3O₂ → 6CO₂ + 6H₂O ΔH = −2011 kJ mol⁻¹

• C₆H₁₂O₆ → 2C₂H₅OH + 2CO₂ ΔH = −69 kJ mol⁻¹

• C₆H₁₂O₆ → 2C₃H₆O₃ ΔH = −120 kJ mol⁻¹

2019 Q26 (51% correct ans)

The calibration factor of a bomb calorimeter was determined by connecting the calorimeter to a power supply. The

calibration was done using 100 mL of water, 6.5 V and a current of 3.6 A for 4.0 minutes. The temperature of the

water increased by 0.48 °C during the calibration.

4.20 g of sucrose underwent complete combustion in the bomb calorimeter. The temperature of the 100 mL of water

increased from 19.6 °C to 25.8 °C.

M(C₁₂H₂₂O₁₁) = 342 g mol⁻¹

The experimental heat of combustion of pure sucrose, in joules per gram, is

• 5.9 × 10⁶

• 7.3 × 10⁴

• 1.7 × 10⁴

• 1.2 × 10⁴

2019 NHT Q28

The component of this breakfast that provides the largest amount of energy per serve is the

• avocado.

• egg.

• fetta cheese.

• rye bread.

2018 Q9

(69% correct ans)

• 100 g of fish

• 80 g of bread

• 40 g of cheese

• 258 g (250 mL) of milk

2017 Q9 (29% correct ans)

Using the information above, the percentage energy content due to protein in an average serving size of this muesli is

• 31.2%

• 29.3%

• 14.0%

• 13.2%

2016 Q10 (80% correct ans)

A student calibrated a calorimeter using an electric heating coil. A current of 1.50 A with a potential difference of

4.50 V was applied for two-and-a-half minutes. A digital probe recorded a temperature rise of 5.35 °C.

The value of the calibration factor, in J °C^–1, is

• 189

• 42.1

• 3.15

• 0.317

2012 (57% correct ans)

• A

• B

• C

• D

2017 Q23 ( 49% correct ans)

For this experiment, the students could maximise

• precision by using a digital thermometer ± 0.2 °C.

• validity by calculating the heat of combustion per mole.

• accuracy by taking samples from three different sources.

• uncertainty by having all students closely follow the same experimental procedure.