1. Explain why it is dangerous to open the radiator cap of an overheated automobile engine 2. A concrete highway is built of slabs 10 m long (at 20' C). How wide should the expansion cracks between the slabs be (at 20"C) to prevent buckling if the range of temperature is -30 "C to +50 'C? 3. What are the following temperatures on the Kelvin scale : (a) 86 .C, (b ) 78-F, (c) - 100'C, (d) 5500 .C, (e) - 459 " F? 4. If 3.00 m' of a gas initially at STP is placed under a pressure of 3.20 atm ., the temperature of the gas rises to 38.0 .C. What is the volume ? 5. Calculate the number of molecules /m' in an ideal gas at STP. 6. If a metal rod had its length increased by 1% when the temperature increased by 100 .C, find the coefficient of linear expansion of this rod is? (a) State four reasons why mercury is widely used in thermometers (b) Calculate at what temperature the Celsius Thermometer and the Fahrenheit Thermometer have the same reading 7. A litre of gas had its temperature reduced from 85.C to 15"C. If the pressure was kept constant what was the percentage reduction in volume ? (a) How many moles of water are there in 1.000L ? (b) How many molecules ? 8. If 40 kcal of heat is added to 2.0 kg of water , what is the resulting temperature change ? 9. A person tries to heat up her bath water by adding 8 L of water at 80'C to 70 L of water at 40 C. What is the final temperature of the water if no heat is lost ? 10. 50 g of lead (c = 0.11 kcal /kg -C) at 100 C is put into 75 g of water at 0"C. What is the final temperature of the mixture ? A) 2"C B) 6.8 .C C) 25 -C D ) 50 * C 11 . What is the specific heat of a metal substance if 135 kJ of heat is needed to raise 5.1 kg of the metal from 18.0 C to 31.5 .C? 12. A 5000-W heater is used to heat water. How many minutes will it take to heat 20 kg