1 0.21K
2 94.5K
3 20m
4 150m
5 0.294K
6 360 000J (360kJ)
7 240 000J (240kJ)
8 14K
9 350 ms-1
Monday, March 27, 2006
Tuesday, March 14, 2006
Latent Heat Answers
1. 25 860 J
2. 60 120 J
3. 4200J
4. 0.048 kg
5. Space = steam at 100 deg
Cloud of steam = condensed stem ie water vaopur at a lower temp, as heat has been lost it condenses.
6. 562.5 s
7. 2.25 x 10E6 Jkg-1
8. 387 s
9. 335 000 Jkg-1
10. 336 000 Jkg-1
11. ditto
12. 1.02 x 10E6 Jkg-1
Apologies for formatting
This homework is now closed
2. 60 120 J
3. 4200J
4. 0.048 kg
5. Space = steam at 100 deg
Cloud of steam = condensed stem ie water vaopur at a lower temp, as heat has been lost it condenses.
6. 562.5 s
7. 2.25 x 10E6 Jkg-1
8. 387 s
9. 335 000 Jkg-1
10. 336 000 Jkg-1
11. ditto
12. 1.02 x 10E6 Jkg-1
Apologies for formatting
This homework is now closed
Wednesday, March 08, 2006
Y12 Homework
Pressure in Fluids
A dam is 200 m long and 20 m deep. Find the total force exerted by the water on the dam.
A vertical tube 0.80 m long is one-quarter full of mercury of density 13 600 kg m-3 and three-quarters full of paraffin of density 800 kg m-3. What pressure do the liquids at the bottom of the tube exert?
The height of the mercury barometer is 750 mm. If the density of mercury is 13 600 kg m-3, what is the atmospheric pressure? (atmospheric pressure holds up the mercury)
A vertical U-tube contains a column of water balanced by a column of paraffin. (draw a diagram) The top of the water column is 0.40 m above the common level and the top of the paraffin column is 0.50 m above the common level. (ie their weight is equal) What is the density of paraffin?
If the mercury barometer reads 760 mmHg, find the atmospheric pressure in millibars. The density of mercury is 13 600 kg m-3 and 1 mbar = 10 N m -2.
A mercury barometer reads 758 mm at sea level and 708 mm at the top of a mountain. If the density of mercury is 13 600 kg m-3 and the average density of the air is 1.25 kg m-3, what is the height of the mountain?
A dam is 200 m long and 20 m deep. Find the total force exerted by the water on the dam.
A vertical tube 0.80 m long is one-quarter full of mercury of density 13 600 kg m-3 and three-quarters full of paraffin of density 800 kg m-3. What pressure do the liquids at the bottom of the tube exert?
The height of the mercury barometer is 750 mm. If the density of mercury is 13 600 kg m-3, what is the atmospheric pressure? (atmospheric pressure holds up the mercury)
A vertical U-tube contains a column of water balanced by a column of paraffin. (draw a diagram) The top of the water column is 0.40 m above the common level and the top of the paraffin column is 0.50 m above the common level. (ie their weight is equal) What is the density of paraffin?
If the mercury barometer reads 760 mmHg, find the atmospheric pressure in millibars. The density of mercury is 13 600 kg m-3 and 1 mbar = 10 N m -2.
A mercury barometer reads 758 mm at sea level and 708 mm at the top of a mountain. If the density of mercury is 13 600 kg m-3 and the average density of the air is 1.25 kg m-3, what is the height of the mountain?
Thursday, March 02, 2006
y12 Homework
Latent Heat
Latent Heat of fusion of ice = 3.36 x 105 J kg-1
Latent Heat of vaporization of water = 2.25 x 106 J kg-1
Specific heat capacity of water = 4200 J kg-1 K-1
How much heat energy is needed to change 0.010 kg of water at 20oC to steam at 100oC?
How much heat energy is needed to change 0.020 kg of ice at 0°C into steam at 100°C?
How much heat energy is needed to melt 0.010 kg of ice at 0o C and then heat the water formed to 20o C?
What mass of ice at 0 °C is needed to cool 0.086 kg of water from 54 °C to 6 °C?
When a kettle boils a space can be seen between the spout and the so called `cloud of steam'. If your finger were placed in the space a much more serious scald would result than if it were placed in the `cloud of steam'. Explain why, and criticize the expression `cloud of steam'.
A heating coil takes 14 min to heat 0.20 kg of water from 20 °C to boiling point. How much longer will it take to boil away 0.02 kg of the boiling water?
A 1 kW immersion heater takes 225 s to boil away 0.1 kg of water at 100 °C. Find the specific latent heat of vaporization of water.
How long will it take an immersion heater of power 500 W to boil away a mixture of 0.05 kg of water and 0.02 kg of ice initially at 0 °C?
A mixture of ice and water at 0 °C contains 0.060 kg of ice. A 750 W immersion heater takes 26.8 s to melt all the ice. Deduce a value for the specific latent heat of fusion of ice.
A mixture of ice and water at 0 °C has a total mass of 1 kg, and contains 0.5 kg of ice. An immersion heater melts all the ice in 168 s, and then needs a further 84 s to heat the mixture to 20 °C. Find the specific latent heat of fusion of ice.
A vessel of heat capacity 115 J K-1 contains 0.30 kg of water and 0.20 kg of ice at 0 °C. An immersion heater takes 134.4 s to melt the ice and a further 88.6 s to heat the vessel and its contents to 20 °C. Find the specific latent heat of fusion of ice.
A heating coil takes 115 s to heat 0.05 kg of a liquid from 20 °C to its boiling-point of 80 °C. It needs a further 340 s to boil away 0.02 kg of the liquid. If the specific heat capacity of the liquid is 2300 J kg-1 K-1, find its specific latent heat of vaporization.
Latent Heat of fusion of ice = 3.36 x 105 J kg-1
Latent Heat of vaporization of water = 2.25 x 106 J kg-1
Specific heat capacity of water = 4200 J kg-1 K-1
How much heat energy is needed to change 0.010 kg of water at 20oC to steam at 100oC?
How much heat energy is needed to change 0.020 kg of ice at 0°C into steam at 100°C?
How much heat energy is needed to melt 0.010 kg of ice at 0o C and then heat the water formed to 20o C?
What mass of ice at 0 °C is needed to cool 0.086 kg of water from 54 °C to 6 °C?
When a kettle boils a space can be seen between the spout and the so called `cloud of steam'. If your finger were placed in the space a much more serious scald would result than if it were placed in the `cloud of steam'. Explain why, and criticize the expression `cloud of steam'.
A heating coil takes 14 min to heat 0.20 kg of water from 20 °C to boiling point. How much longer will it take to boil away 0.02 kg of the boiling water?
A 1 kW immersion heater takes 225 s to boil away 0.1 kg of water at 100 °C. Find the specific latent heat of vaporization of water.
How long will it take an immersion heater of power 500 W to boil away a mixture of 0.05 kg of water and 0.02 kg of ice initially at 0 °C?
A mixture of ice and water at 0 °C contains 0.060 kg of ice. A 750 W immersion heater takes 26.8 s to melt all the ice. Deduce a value for the specific latent heat of fusion of ice.
A mixture of ice and water at 0 °C has a total mass of 1 kg, and contains 0.5 kg of ice. An immersion heater melts all the ice in 168 s, and then needs a further 84 s to heat the mixture to 20 °C. Find the specific latent heat of fusion of ice.
A vessel of heat capacity 115 J K-1 contains 0.30 kg of water and 0.20 kg of ice at 0 °C. An immersion heater takes 134.4 s to melt the ice and a further 88.6 s to heat the vessel and its contents to 20 °C. Find the specific latent heat of fusion of ice.
A heating coil takes 115 s to heat 0.05 kg of a liquid from 20 °C to its boiling-point of 80 °C. It needs a further 340 s to boil away 0.02 kg of the liquid. If the specific heat capacity of the liquid is 2300 J kg-1 K-1, find its specific latent heat of vaporization.
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