 µ IB | Thermal

10 quick questions

10 minutes maximum! (can you do it in 5?)

1. Steam has a high internal energy and can cause severe burns. Internal energy is defined as...

• A. the total intermolecular potential and random kinetic energy of the molecules of a substance.
• B. the total intermolecular potential energy only.
• C. the total kinetic energy only.
• D. the total kinetic, potential and chemical energy stored in a substance.

2. 1 kg of sea water at 20 0C has a specific heat capacity of cw. What is the specific heat capacity of 2 kg of sea water at 40 0C?

• A. ½cw
• B. cw
• C. 2cw
• D. 4cw

3-5. The graph shown below shows the temperature change of solid lead as heat energy is supplied, and the lead melts. Heat energy is transferred at a constant rate. 3. Which feature of the graph above shows the specific heat capacity of solid lead?

• A. The gradient of line z.
• B. The gradient of line x.
• C. The length of line y.
• D. The area under line y.

4. Which feature of the graph above shows the specific heat capacity of liquid lead?

• A. The gradient of line z.
• B. The gradient of line x.
• C. The length of line y.
• D. The area under line y.

5. Which feature of the graph above shows the latent heat of fusion of lead?

• A. The gradient of line z.
• B. The gradient of line x.
• C. The length of line y.
• D. The area under line y.

6. The temperature of 2 substances, P and Q, are stated as 200 0C and -100 0C. In units of kelvin (K), this is....

• A. P = 73 K, Q = -373 K
• B. P = 173 K, Q = 473 K
• C. P = 473 K, Q = 373 K
• D. P = 473 K, Q = 173 K
7. Approximately 4000 J of energy is needed to heat 1 kg of copper by 10 0C. How much energy is needed to heat 0.5 kg of copper by 40 0C? • A. 16 kJ
• B. 2 kJ
• C. 1 kJ
• D. 8 kJ

8-10. A sample of 1 kg of liquid is heated by a 100 W electric heater. The graph shows the increase in temperature with time: 8. What is total heat energy Q suppiled to the liquid in this time?

• A. 10 000 J
• B. 20 000 J
• C. 1 000 J
• D. 2 000 J

9. Which of the following formulas can be used to calculate the specific heat capacity c of the liquid? 10. The experiment is repeated, once with double the mass of the same liquid, and a second time with a liquid of lower specific heat capacity. What effect would this have on the gradient of the graph above?

 Higher mass of liquid Liquid of lower specific heat capacity A gradient of line decreases gradient of line decreases B gradient of line decreases gradient of line increases C gradient of line increases gradient of line decreases D gradient of line increases gradient of line increases