Specific heat capacity & Latent heat

Find the energy released by a copper block when it is cooled from 100^°C to 20^°C. Given that the heat capacity of the block is 770 J^°C^-1.

• 7.70x10⁴ J

• 8.61x10⁴ J

• 6.16x10⁴ J

• 5.02x10⁴ J

Which of the following statements is correct?

• The unit of heat capacity is J kg^{-1 °}C^-1.

• Specific heat capacity measures the temperature variations when 1J of energy is absorbed.

• The unit of specific heat capacity is J kg^-1 K^-1.

• Specific heat capacity equals to the heat content of an object.

When an electric heater is supplied with an electric power of 2.0 kW to heat 4.0 kg of water for 1 minute, calculate the increase in temperature of the water. Assume that the specific heat capacity of water is 4200 J kg^{-1 0}C^-1 and there is no heat loss to the surroundings.

• 3.05⁰C

• 7.1⁰C

• 14⁰C

• 30⁰C

Danny pours some 95°C water into a cup of instant noodles. The final temperature of the mixture is 85°C. If the masses of the hot water and noodles are 500 g and 150 g respectively, find the specific heat capacity of the noodles.

Give that the original temperature of the noodles is 25°C and the specific heat capacity of the water is 4200 J kg^-1 °C^-1.

• 500 J kg^-1 °C^-1

• 1.08 x 10³ J kg^-1 °C^-1

• 2.33 x 10³ J kg^-1 °C^-1

• 6.00 x 10³ J kg^-1 °C^-1

In order to make a cup of milk coffee at 78°C, 200 g of coffee is mixed up with 40 g of milk. If the original temperature of the coffee is 80°C, find the original temperature of the milk. Assume that there is no heat lost to the surroundings. Given that the specific heat capacity of coffee and milk are 4000 J kg^-1 °C^-1 and 3900 J kg^-1 °C^-1 respectively.

• 10.3°C

• 20.7°C

• 45.2°C

• 67.7°C

Gas is trapped in a closed container. There exists gas pressure inside the container because gas molecules

• move randomly.

• move with equal speed.

• collide with one another.

• collide constantly with the walls of container.

Given that the specific latent heat of fusion of a sample is 550 kJ kg^-1. Which of the following is correct?

• The mass of this sample is 1 kg.

• The energy needed to increase the temperature of 1 kg of this sample in solid state through 1^oC is 550 kJ.

• The energy needed to increase the temperature of 1 kg of this sample in liquid state through 1^oC is 550 kJ.

• The energy needed to change 1 kg of the material from solid state to liquid state is 550 kJ.

Find the energy released by 0.3 kg of a liquid sample at 200^oC to change to its solid state at 50^oC. Given that the specific heat capacity of the sample in solid state and liquid state are 770 J kg^{-1 o}C^-1 and 900 J kg^{-1 o}C^-1 respectively.

The melting point of the sample is 100^oC and the specific latent heat of fusion of it is 10 kJ kg^-1.

• 4.17 x 10³ J

• 8.86 x 10³ J

• 2.10 x 10⁴ J

• 4.16 x 10⁴ J

If 5.0 x 10⁵ J of energy is absorbed by a block of ice when it is heated from -5^oC to 0^oC, find the mass of the ice.

Given that the specific heat capacity of ice is 2.05 x 10³ J kg^{-1 o}C^-1 and the specific latent heat of fusion of ice is 3.34 x 10⁵ J kg^-1.

• 1.45 kg

• 2.56 kg

• 3.01 kg

• 3.27 kg

Regarding to the fixed points in Celsius scale, which of the following is correct?

• The upper fixed point is the freezing point of water and the lower fixed point is the boiling point of water.

• The upper fixed point is the boiling point of methane and the lower fixed point is the freezing point of methane.

• The upper fixed point is the boiling point of water and the lower fixed point is the freezing point of ice.

• The upper fixed point is the melting point of ice and the lower fixed point is the freezing point of ice.