Q1Written answer
Convert the following temperature to Celsius scale:
a. 300K b. 573K
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Worked solution
a. 0°C=273K
300K= (300-273)°C = 27°C
b. 573K= (573-273)°C = 300°C
NCERT · Class 9 · Science
Chapter 1: Matter in Our Surroundings
Practice each question, then open the answer or worked solution.
Exercise – 1.4
Textbook page 9 · 4 questionsQ2Written answer
What is the physical state of water at:
a. 250°C b. 100°C ?
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Worked solution
(a) At 250°C – Gaseous state since it is beyond its boiling point.
(b) At 100°C – It is at the transition state as the water is at its boiling point. Hence it would be present in both liquid and gaseous states.
Q3Written answer
For any substance, why does the temperature remain constant during the change of state?
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Worked solution
It is due to the latent heat as the heat supplied to increase the temperature of the substance is used up to transform the state of matter of the substance; hence, the temperature stays constant.
Q4Written answer
Suggest a method to liquify atmospheric gases.
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Worked solution
It can be achieved by either increasing the pressure or decreasing the temperature, which ultimately leads to the reduction of spaces between molecules.