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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?
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उत्तर १
It can be concluded from the P-T phase diagram of CO2 that:
- CO2 is gaseous at –70°C, under 1 atm pressure
- CO2 is solid at –60°C, under 10 atm pressure
- CO2 is liquid at 15°C, under 56 atm pressure
उत्तर २
- The point (- 70 °C, 1.0 atm) lies in the vapour region. Hence, CO2 is vapour at this point.
- The point (- 60 °C, 10 atm) lies in the solid region. Hence, CO2 is solid at this point.
- The point (15 °C, 56 atm) lies in the liquid region. Hence, CO2 is liquid at this point
संबंधित प्रश्न
A copper block of mass 2.5 kg is heated in a furnace to a temperature of 500 °C and then placed on a large ice block. What is the maximum amount of ice that can melt? (Specific heat of copper = 0.39 J g–1 K–1; heat of fusion of water = 335 J g–1).
Answer the following questions based on the P–T phase diagram of CO2:
CO2 at 1 atm pressure and temperature – 60 °C is compressed isothermally. Does it go through a liquid phase?
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:
At what temperature and pressure can the solid, liquid and vapour phases of CO2 co-exist in equilibrium?
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?
Mark the correct options:
- A system X is in thermal equilibrium with Y but not with Z. System Y and Z may be in thermal equilibrium with each other.
- A system X is in thermal equilibrium with Y but not with Z. Systems Y and Z are not in thermal equilibrium with each other.
- A system X is neither in thermal equilibrium with Y nor with Z. The systems Y and Z must be in thermal equilibrium with each other.
- A system X is neither in thermal equilibrium with Y nor with Z. The system Y and Z may be in thermal equilibrium with each other.
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.
Relation between heat Q, mass mmm, and specific latent heat L:
What happens to temperature at 0°C during melting of ice?
Why does water stay at 100°C while boiling?
Effect of increasing external pressure on boiling point:
