Problem Solving

• In a chemistry experiment, 0.00020 m³ (200 cm³) of gas was collected in a flask at a pressure of 125 kPa. Calculate the volume of this mass of gas at a pressure of 100 kPa and the same temperature. 

  Answer: 0.00025 m³
• A gas occupies a volume of 2.5 liters at a pressure of 3.0 atmospheres. If the volume is decreased to 1.5 liters while the temperature remains constant, what is the new pressure?

  Answer: 5.0 atmospheres
• A gas is initially at a pressure of 200 kPa and occupies a volume of 4.0 m³. If the volume is increased to 6.0 m³ while the temperature remains constant, what is the new pressure?

  Answer: 133.33 kPa
• Find the final temperature of 800 g of water at an initial temperature of 20℃ after 20 kJ of energy has been transferred to it. The specific heat capacity of water is 4200 J/kg ℃. 

  Answer: 25.95 ℃
• An iron has an aluminium plate with a mass of 1.5 kg. Calculate the thermal energy stored in the plate when the temperature rises from 20℃ to 200℃. The specific heat capacity of aluminium is 913 J/kg ℃. 

  Answer: 246510 J