Phys Heat Test Review

Heat necessary to change the phase or state of matter of a substance is called __.

• internal energy

• latent heat

• kinetic energy

• none of the above

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

• 7.70x10⁴ J

• 8.61x10⁴ J

• 6.16x10⁴ J

• 5.02x10⁴ J

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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.

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

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Latent heat is

• the heat absorbed or released at a boiling process during a change of phase

• the heat absorbed or released at a constant temperature during a change of phase

• the heat absorbed or released at a constant temperature during a change of phase of 1 kg object

• the heat absorbed or released by an object to increase or decrease its temperature by 1 degree Celcius

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NGSS.HS-PS3-4

The heat absorbed by melting a solid is known as

• latent heat of fusion

• latent heat of solid

• latent heat of liquid

• latent heat of vaporisation

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the symbol for specific latent heat is

• c

• Q

• m

What is the formula to calculate specific latent heat of fusion?

• c = Q/(mΔƟ)

• Q = mcΔƟ

Tags

NGSS.HS-PS3-4

The graph shows the cooling curve of a substance. At which stages the specific latent heat released?

• AB and CD

• BC and DE

• AB and EF

• BC and CD

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NGSS.HS-PS3-2

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