P-1 Heat Science - P-1 Heat

Water expands on reducing its temperature below………..°C. (March 2019)

………..heat is needed to convert 1 g of water at 0 °C and at a pressure of one atmosphere into 1 g of steam under the same conditions.

………..heat is needed to raise the temperature of 1 kg of water from 14.5 °C to 15.5 °C.

The density of water is maximum at………..

At 4 °C, the density of water is………..

State the relation between the kilocalorie and the calorie.

A copper calorimeter of mass 100 g and temperature 30 °C contains water of mass 200 g and temperature 30 °C. If a piece of ice of mass 40 g and temperature 0 °C is added to it, what will be the maximum temperature of the mixture? [c (copper) = 0.1 cal/g·°C, c (water) = 1 cal/g·°C, L = 80 cal/g]

State the units of heat.

What is humidity?

You know that as we go higher than the sea level, the boiling point of water decreases. What would be the effect on the melting point of a solid?

The outer surface of a beaker containing ice cubes becomes wet in a short while.

A plastic bottle, completely filled with water, when kept in a freezer, is likely to break.

When you enter a warm room after being outside on a frosty early morning, your spectacles ‘steam up’.

During cold nights, sometimes dew is formed.

Water droplets are seen on’ the outer surface of a cold drink bottle.

Observe the following graph. Considering the change in volume of water as its temperature is raised from 0 °C, discuss the difference in the behaviour of water and other substances. What is this behaviour of water called?

Water of mass 200 g and temperature 30 °C is taken in a copper calorimeter of mass 50 g and temperature 30 °C. A copper sphere of mass 100 g and temperature 100 °C is released into it. What will be the maximum temperature of the mixture? [c (water) = 1 cal/g·°C, c (copper) =0.1 cal/g·°C]

Find the heat needed to raise the temperature of a piece of iron of mass 500 g by 20 °C. (c = 0.110 cal/g·°C)

If water of mass 60 g and temperature 60 °C is mixed with water of mass 60 g and temperature 40 °C, what will be the maximum temperature of the mixture?

If water of mass 60 g and temperature 50 °C is mixed with water of mass 40 g and temperature 30 °C, what will be the maximum temperature of the mixture?

Explain how dew and fog are formed.
(OR)
Write a short note on formation of dew and fog.

A mountaineer climbing on the Everest, experienced the following facts. Explain each fact with the scientific reason : (1) He found j fishes alive below the ice (2) Time required for cooking was more as he went higher (3) He saw many times cliffs falling suddenly (4) He saw tubes carrying water broken.

Write scientific reason. Even the wire moves through the ice slab , the ice slab does not break. ###During experiment, the wire moves through the ice slab. However, the ice slab does not break. Why?

If steam of mass 100 g and temperature 100 °C is released on an ice slab of temperature 0 °C, how much ice will melt?

Find the heat needed to raise the temperature of a silver container of mass 100 g by 10 °C. (c = 0.056 cal/g.°C)

Explain how the specific heat capacity of a solid can be determined (measured) by the method of mixture.

Draw a neat labelled diagram of Hope’s apparatus. Explain how this apparatus can be used to demonstrate anomalous behaviour of water. Draw a graph of temperature of water against time.

How will you explain the following statements with the help of the anomalous behaviour of water?
(1) In regions with cold climate, the aquatic plants and animals can survive even when the atmospheric temperature goes below 0 °C.
(2) In cold regions in winter the pipes for water supply break and even rocks crack.

 A calorimeter has mass 100 g and specific heat 0.1 kcal/kg ·°C. It contains 250 g of liquid at 30 °C having specific heat of 0.4 kcal/kg·°C. If we drop a piece of ice of mass 10 g at 0 °C into the liquid, what will be the temperature of the mixture?

A thermally insulated pot has 150 g ice at temperature 0 °C. How much steam of 100 °C has to he mixed to it, so that water of temperature 50 °C will be obtained?
(Given: Latent heat of melting of ice = 80 cal/g, latent heat of vaporization of water = 540 cal/g, specific heat of water = 1 cal/g °C)

Absolute humidity is expressed in kg/m3.

Relative humidity has no unit.

If the relative humidity is less than 60%, we feel that the air is dry.

If the relative humidity is more than 60%, we feel that the air is humid.

Latent heat of fusion, Q = mL.