In text questions page number 9
Question1. Convert the following temperature to Celsius scale: a. 300 K b. 573 K.
Answer: To concert Kelvin scale into Celsius scale we have to subtract 273 so (a) 300K=300-273=27 ºC, (b) 573K=573-273=300 ºC
Question 2. What is the physical state of water at: a. 250ºC, b. 100ºC?
Answer: (a) At 250ºC water exist in only gaseous state. (b) At 100ºC water exist in both gaseous and liquid state.
Quesiton 3. For any substance, why does the temperature remain constant during the change of state?
Answer: The temperature remain constant during the change of state because the heat supplied is used up in changing the state of matter as it has to work against the force of attraction of molecules.
Question 4. Suggest a method to liquefy atmospheric gases.
Answer: The gases can be converted into liquids by bringing its particles closer so atmospheric gases can be liquefied either by decreasing temperature or by increasing pressure.