2.2.2a Internal energy and temperature

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Question 43

A student investigates the thermal properties of dry soil and water.

She is provided with the following temperatures at the beginning of the experiment:

Room temperature (initial temperature of soil and cold water), $θS=21.0∘C\theta_{\text{S}} = 21.0^\circ\text{C}$
Initial temperature of hot water, $θH=85.0∘C\theta_{\text{H}} = 85.0^\circ\text{C}$

She pours 100 cm³ of hot water into a beaker containing dry soil at room temperature. After stirring, she measures the highest temperature reached by the mixture:

\theta_{\text{M1}} = 73.0^\circ\text{C}

Calculate the temperature rise $θR\theta_{\text{R}}$ of the soil using the equation $θR=θM1−θS\theta_{\text{R}} = \theta_{\text{M1}} - \theta_{\text{S}}$ .
Calculate the temperature fall $θF\theta_{\text{F}}$ of the hot water using the equation $θF=θH−θM1\theta_{\text{F}} = \theta_{\text{H}} - \theta_{\text{M1}}$ .
Calculate the ratio $S\,$ using the equation $S=θRθF\displaystyle S = \frac{\theta_{\text{R}}}{\theta_{\text{F}}}$ . Give your answer to a suitable number of significant figures.

[3]

She pours 100 cm³ of hot water into a clean beaker containing 100 cm³ of cold water at room temperature. After stirring, she measures the highest temperature reached by this mixture:

\theta_{\text{M2}} = 51.0^\circ\text{C}

Calculate the temperature rise $θR\theta_{\text{R}}$ of the cold water using the equation $θR=θM2−θS\theta_{\text{R}} = \theta_{\text{M2}} - \theta_{\text{S}}$ .
Calculate the temperature fall $θF\theta_{\text{F}}$ of the hot water using the equation $θF=θH−θM2\theta_{\text{F}} = \theta_{\text{H}} - \theta_{\text{M2}}$ .
Calculate the ratio $W\,$ using the equation $W=θRθF\displaystyle W = \frac{\theta_{\text{R}}}{\theta_{\text{F}}}$ .

[3]

The student predicts that $S\,$ should be equal to $\times W$ . State whether the results support this prediction. Justify your answer by comparison of the calculated values.

[2]

Explain briefly what the student does after pouring the hot water into the beaker and before taking the temperature, in order to obtain a reliable value for the maximum temperature.
The student measures the volume of the dry soil using a measuring cylinder before beginning. Select which of these precautions she should take to obtain an accurate reading (select all that apply):
- Take the reading at the bottom of the meniscus.
- Tap the measuring cylinder gently to make sure the top of the soil is horizontal.
- View the scale of the measuring cylinder at right angles.

[3]

She pours 100 cm³ of hot water into a beaker containing dry soil at room temperature. After stirring, she measures the highest temperature reached by the mixture:

\theta_{\text{M1}} = 73.0^\circ\text{C}

Calculate the temperature rise $θR\theta_{\text{R}}$ of the soil using the equation $θR=θM1−θS\theta_{\text{R}} = \theta_{\text{M1}} - \theta_{\text{S}}$ .
Calculate the temperature fall $θF\theta_{\text{F}}$ of the hot water using the equation $θF=θH−θM1\theta_{\text{F}} = \theta_{\text{H}} - \theta_{\text{M1}}$ .
Calculate the ratio $S\,$ using the equation $S=θRθF\displaystyle S = \frac{\theta_{\text{R}}}{\theta_{\text{F}}}$ . Give your answer to a suitable number of significant figures.

2.2.2a Internal energy and temperature

Question 43

Markscheme

2.2.2a Internal energy and temperature

Question 43

Markscheme

2.2.2a Internal energy and temperature

Question 43

2.2.2a Internal energy and temperature Questions

2.2.2a Internal energy and temperature

Question 43

2.2.2a Internal energy and temperature Questions