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Why do clothes dry slowly in winter?

Important Questions on Water

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Science>Chemistry>Water>Water Cycle

Useful substance in preparation of freezing mixture is

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Science>Chemistry>Water>Water Cycle

Which gas boils out first during fractional distillation of air.

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Science>Chemistry>Water>Water Cycle

When does ice melt at the same temperature $0 ° C$ (273 Kelvin), which one of the following has more energy?

EASY

Science>Chemistry>Water>Water Cycle

"Spirit kept in an open watch glass is converted into gaseous state even at room temperature". Explain.

HARD

Science>Chemistry>Water>Water Cycle

The melting point of naphthalene is

80 ° C

and the room temperature is

30 ° C

. A sample of liquid naphthalene at

100 ° C

is cooled down to the room temperature. Draw a temperature time graph to represent this cooling. In the graph, mark the region which corresponds to the freezing process.

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Science>Chemistry>Water>Water Cycle

Which of the following curves best represents the variation in density of water with temperature?

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Science>Chemistry>Water>Water Cycle

Latent heat of vaporisation is

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Science>Chemistry>Water>Water Cycle

Dry ice is

HARD

Science>Chemistry>Water>Water Cycle

An earthen pitcher used in summer cools water in it essentially by evaporation of water from its porous surface. If a pitcher carries

4 kg

of water and the rate of evaporation is

20 g

per hour, temperature of water in it decreases by

Δ T

in two hours. The value of

Δ T

is close to (ratio of latent heat of evaporation to specific heat of water is

540 ° C

)

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Science>Chemistry>Water>Water Cycle

Explain the liquefaction and zone refining method of refining of metals. (draw diagram)

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Science>Chemistry>Water>Water Cycle

The Clausius-Clayperon equation helps to calculate

HARD

Science>Chemistry>Water>Water Cycle

1 kg

of ice at

- 20^{o} C

is mixed with

2 kg

of water at

90^{o} C

. Assuming that there is no loss of energy to the environment, what will be the final temperature of the mixture? (Assume latent heat of ice

= 334.4 kJ {(kg)}^{- 1}

, specific heat of water and ice are

4.18 kJ {(kg - K)}^{- 1}

and

2.09 kJ {(kg - K)}^{- 1}

, respectively.)

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Science>Chemistry>Water>Water Cycle

A Carnot freezer takes heat from water at

0^{o} C

inside it and rejects it to the room at a temperature of

27^{o} C .

The latent heat of ice is

336 \times 10^{3} J k g^{- 1} .

If 5kg of water at

0^{o} C

is converted into ice at

0^{o} C

by the freezer, then the energy consumed by the freezer is close to :

HARD

Science>Chemistry>Water>Water Cycle

Assume that a drop of a liquid evaporates by a decrease in its surface energy so that its temperature remains unchanged. The minimum radius of the drop for this to be possible is. (The surface tension is

T

, the density of the liquid is

ρ

and

L

is its latent heat of vaporisation.)

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Science>Chemistry>Water>Water Cycle

Convert the following temperatures to the Kelvin scale:

a. $25 ° C$

b. $373 ° C$ ?

HARD

Science>Chemistry>Water>Water Cycle

Suggest an experiment to demonstrate the compressibility of gases and liquids.

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Science>Chemistry>Water>Water Cycle

Define evaporation. Give an example that indicates that evaporation is an endothermic process.

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Science>Chemistry>Water>Water Cycle

Is evaporation an endothermic or exothermic process? Give one example to support your answer.

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Science>Chemistry>Water>Water Cycle

The following questions based on the $P - T$ phase diagram of carbon dioxide:
At what temperature and pressure can the solid, liquid and vapour phases of $C O_{2}$ co-exist in equilibrium?
Question Image

HARD

Science>Chemistry>Water>Water Cycle

Why does the temperature remain constant during the change of state?

Why do clothes dry slowly in winter?

Important Questions on Water

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