4.1Understanding Thermal Equilibrium . / 42 X100=

CHAPTER 4 : HEAT

4.1Understanding Thermal Equilibrium [……. / 42 x100=………]

A student is able to:

4.1.1Explain thermal equilibrium

4.1.2Explain how a liquid-in-glass thermometer works

* Choose the correct word in the bracket.

1.*( Heat , Temperature ) is the degree of hotness of a body.

2.*( Heat , Temperature ) is a form of energy.

3.A hot body has a …………… temperature whereas a cold body has a

………………… temperature.

4.The SI unit for heat is …………….

5.The SI unit for temperature is …………

6.Temperature is a *( base , derived ) quantity.

7.Heat is a *( base , derived ) quantity.

8.The figure shows two metal blocks in thermal contact.

(a) Energy is transferred from *( A , B ) to *( A , B ) at a faster rate.

(b) Energy is transferred from *( A , B ) to *( A , B ) at a slower rate.

(d) Temperature B will *( increase , decrease ).

(e) The net heat will flow from *( A , B ) to *( A , B ) until they are at the

same temperature.

9.Two bodies are said to be in thermal equilibrium when :

(a) they are at the *( zero , same ) temperature.

(b) the net rate of heat flow between the two bodies is *( zero , same ).

10.Temperature is measured by a ………………..with works with the principle of

……………………….

11.Name the physical property (thermometric property) which varies with temperature used in a liquid-in-glass thermometer.

………………………..

12.The liquids commonly used in liquid-in-glass thermometers are ……………….

and ………………….

13.Comparison of mercury and alcohol as a liquid-in-glass thermometer.

Mercury / Alcohol
Freezing point :
Boiling point : / Freezing point :
Boiling point :
It *(wet, does not wet) the tube. / It *(wet, does not wet) the tube.
*(Opaque , colourless)
Easy to read. / *(Opaque , colourless)
It needs to be dyed.
It is *(poisonous, safe liquid). / It is *(poisonous, safe liquid).
It is *(cheap, expensive). / It is *(cheap, expensive).
Conducts heat well, responds faster to temperature changes. / Responds more slowly then mercury.

14.Complete the following table concerning a liquid-in-glass thermometer.

Features / Explanation
The glass bulb is thin.
The bulb is made small.
The bore of the capillary tube is narrow and uniform.
The walls of the long tube above the bulb are made thick

15.Temperature of liquid, ,

Where, = length of mercury at …………….. point.

= length of mercury at …………….. point.

= length of mercury at point.

16.An uncalibrated thermometer is attached to a centimetre scale and reads

5.0 cm in pure melting ice and 30.0 cm in steam. When the thermometer is immersed in the liquid y, the length of the mercury column is 15.0 cm. What is temperature of liquid y?

4.2Understanding Specific Heat Capacity[……. / 17 x100=………]

A student is able to:

4.2.1Define specific heat capacity I

4.2.2State that c= Q

mθ

4.2.3Determine the specific heat capacity of a liquid

4.2.4Determine the specific heat capacity of a solid

4.2.5Describe applications of specific heat capacity

4.2.6Solve problems involving specific heat capacity

1.The ………………………………………………………… of a substance is the quantity of heat needed to increase the temperature of a mass of 1 kg by

1C or 1 K.

2.Specific heat capacity, c =

Where, m = …………………

Q = ……………………………………………………

= …………………………………………………….

3.The unit of specific heat capacity is ………………….

4.The quantity of heat absorbed or lost from a body is given by, Q = ……………

5.How much heat energy is required to raise the temperature of 1.5 kg of water from 30 C to its boiling point ? The specific heat capacity of water is 4200 J kgC.

6.Conversion of energy

(a)Electrical energy from heater transformed into heat energy.

……… = m c

(b)Potential energy of a falling object transformed into heat energy.

……… = m c

7.A 700 W electric heater is used to heat 2 kg of water for 10 minutes. Calculate the temperature rise of the water. The specific heat capacity of water is 4200 J kgC.

8.A copper block weighing 2 kg is dropped from a height of 20 m. What is the rise in temperature of the copper block after it hits the floor. The specific heat capacity of copper is 400 J kgC.

9.A bullet traveling at 60 m s hit a sand bag. The temperature of the bullet rises by 4.5 C. Calculate the specific heat capacity of the bullet.

10.100 g of hot water at 90Cis mixed with 200 g of cold water at 30C. Assuming that no heat is lost, calculate the final temperature of the mixture.

11.Complete the following table.

Material has a high specific heat capacity / Material has a low specific heat capacity
It takes a longer time to be heated.
It lose heat easily.
It is a heat insulator.

4.3Understanding Specific Latent Heat [……. / 21 x100=………]

A student is able to:

4.3.1State that transfer of heat during a change of phase does not cause a change in temperature

4.3.2Define specific latent heat (l)

4.3.3State that l = Q

4.3.4Determine the specific latent heat of fusion

4.3.5Determine the specific latent heat of vaporization

4.3.6Solve problems involving specific latent heat

1.Matter exists in three states, that is solid,……………. and ………….. .

2.The heat released or absorbed at constant temperature during a change of state of matter is known as ……………….. .

3. Latent heat is released

Melting ……………

……………… condensation

……………………………

4.Specific latent heat of …………….. is the quantity of heat that is needed to change 1 kg of a substance from solid state to liquid state, without a change in temperature.

5.Specific latent heat of …………….. is the quantity of heat that is needed to change 1 kg of a substance from liquid state to vapour state, without a change in temperature.

6.Specific latent heat, L =

Where, Q = latent heat absorbed or released by the substance

m = mass of the substance.

7.The SI unit for specific latent heat is ………………. .

8.What is the quantity of heat required to melt 2 kg of ice at 0C ? Specific latent heat of fusion of ice = 336000 J kg.

9.Temperature / C

90 D E

B C

30 A

0 5 15 20 35 Time/minute

Figure shows the temperature- time graph for a substance, S of mass 2.0 kg, being heated using a 500 W heater.

(a)Based on the graph state the physical condition of substance, S in

(i)AB : ……………………………………………………………..

(ii)BC : ……………………………………………………………..

(iii)CD : ……………………………………………………………..

(iv)DE : ……………………………………………………………..

(b)Melting point : ………………………………………………………….

(c)Boiling point : ……………………………………………………………

(d)By using kinetic theory, explain why the temperature of substance, S in AB is increasing.

…………………………………………………………………………………

(e)By using kinetic theory, explain why the temperature of substance, S is constant in BC even though heat is still been supplied to it.

…………………………………………………………………………………

(f)Calculate the specific heat capacity of the substance in solid state.

(g)Calculate the specific latent heat of vaporization of substance, S.

4.4Understanding The Gas Laws[……. / 27 x100=………]

A student is able to:

4.4.1Explain gas pressure, temperature and volume in terms of the behavior of gas molecules

4.4.2Determine the relationship between pressure and volume at constant temperature for a fixed mass of gas ie Pv = constant

4.4.3Determine the relationship between volume and temperature at constant pressure for a fixed mass of gas ie

V/T = constant

4.4.3Determine the relationship between pressure and temperature at constant volume for a fixed mass of gas ie

p/T = constant

4.4.4Explain about zero

4.4.5Explain the absolute/Kelvin scale of temperature

4.4.6Solve problems involving the pressure, temperature and volume of a fixed mass of gas

1. Complete the table below about gas laws’

Boyle’s Law / Charles’ Law
P / P T
Constant Variable :
1. Mass of gas
2. / Constant Variable :
1. Mass of gas
2. Pressure of gas / Constant Variable :
1. Mass of gas
2.
Boyle’s law states that the pressure of a fixed mass of gas is inversely proportional to its volume at constant temperature. / Charles’ law states that / Pressure law states that

P

0 V /
V

0 T/C /
P

0 T/C
P
0 / V
0 T/K /
P
0T/K

0 P /

0 V /
0 P

0 V /

0 T /

0 T

2.Figure (a) show 18 cm of air column trapped in a capillary tube by 4 cm of mercury. If the glass tube is inverted, what is the length, L, of the air column trapped in the capillary tube?

(Atmospheric pressure = 76 cm Hg)

4 cm L air

18 cm air 4 cm

( a ) ( b )

3.An air bubble released by a diver has a volume of 4.0 cm at depth of 15 m. What is the volume of the bubble at a depth of 10 m?

(Atmospheric pressure = 10 m water)

4.The value -273C is equivalent to …… K. This temperature is known as the

………………………………………

5.Convert 27C to its equivalent temperature in Kelvin.

6.Convert 330 K to its equivalent temperature in degrees Celsius.

7.The volume of a gas is 5 cm at 27C. The gas is heated at fixed pressure until the column becomes 6 cm. Calculate the final temperature of the gas.

8.A gas of volume 20cm at 47C is heated until its temperature becomes 87C at constant pressure. What is the final volume of the gas?

9.Before a journey from Parit Buntar to Ipoh, the air in a car tyre has a pressure of 200 kPa and a temperature of 27C. After the journey, the air pressure in the tyre is 220 kPa. What is the temperature of the air in the tyre after the journey?

10.The pressure of gas in a light bulb is 50.5 kPa at 30C. Calculate the pressure of the gas when the temperature inside the bulb rises to 87C after the bulb is lighted up.