Advertisements
Advertisements
प्रश्न
During summers in India, one of the common practice to keep cool is to make ice balls of crushed ice, dip it in flavoured sugar syrup and sip it. For this a stick is inserted into crushed ice and is squeezed in the palm to make it into the ball. Equivalently in winter, in those areas where it snows, people make snow balls and throw around. Explain the formation of ball out of crushed ice or snow in the light of P–T diagram of water.
Advertisements
उत्तर
Refer to the P–T diagram of water and the double-headed arrow. Increasing pressure at 0°C and 1 atm take ice into a liquid state and decreasing pressure in a liquid state at O°C and 1 atm takes water to the ice state.
When crushed ice is squeezed, some of it melts, filling up gap between ice flakes upon releasing pressure. This water freezes, binding all ice flakes and making the ball more stable.
APPEARS IN
संबंधित प्रश्न
Answer the following question based on the P-T phase diagram of carbon dioxide:
Is CO2 solid, liquid or gas at
- –70 °C under 1 atm,
- –60 °C under 10 atm,
- 15 °C under 56 atm?
Answer the following questions based on the P–T phase diagram of CO2:
What happens when CO2 at 4 atm pressure is cooled from room temperature at constant pressure?
Answer the following questions based on the P–T phase diagram of CO2:
Describe qualitatively the changes in a given mass of solid CO2 at 10 atm pressure and temperature –65 °C as it is heated up to room temperature at constant pressure.
Answer the following questions based on the P–T phase diagram of CO2:
Describe qualitatively the changes in a given mass of solid CO2 at 10 atm pressure and temperature –65 °C as it is heated up to room temperature at constant pressure.
Answer the following questions based on the P–T phase diagram of CO2:
CO2 is heated to a temperature 70 °C and compressed isothermally. What changes in its properties do you expect to observe?
A ‘thermacole’ icebox is a cheap and efficient method for storing small quantities of cooked food in summer in particular. A cubical icebox of side 30 cm has a thickness of 5.0 cm. If 4.0 kg of ice is put in the box, estimate the amount of ice remaining after 6 h. The outside temperature is 45 °C, and coefficient of thermal conductivity of thermacole is 0.01 J s–1 m–1 K–1. [Heat of fusion of water = 335 × 103 J kg–1]
A brass boiler has a base area of 0.15 m2 and thickness 1.0 cm. It boils water at the rate of 6.0 kg/min when placed on a gas stove. Estimate the temperature of the part of the flame in contact with the boiler. The thermal conductivity of brass = 109 J s –1 m–1 K–1; Heat of vaporisation of water = 2256 × 103 J kg–1.
Explain why a body with large reflectivity is a poor emitter
Answer the following question based on the P-T phase diagram of carbon dioxide:
What is the effect of decrease of pressure on the fusion and boiling point of CO2?
Answer the following question based on the P-T phase diagram of carbon dioxide:
What are the critical temperature and pressure for CO2? What is their significance?
Relation between heat Q, mass mmm, and specific latent heat L ______.
In a heating curve of ice and water, which part represents the latent heat of fusion?
Which statement best explains why the temperature of boiling water remains constant at 100°C until all the water has changed to steam (at 1 atm)?
Why is the latent heat of vaporisation much greater than the latent heat of fusion?
For 1 kg of water, which phase change requires more energy?
