Advertisements
Advertisements
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).
Advertisements
उत्तर १
Mass of the copper block, m = 2.5 kg = 2500 g
Rise in the temperature of the copper block, Δθ = 500°C
Specific heat of copper, C = 0.39 J g–1 °C–1
Heat of fusion of water, L = 335 J g–1
The maximum heat the copper block can lose, Q = mCΔθ
= 2500 × 0.39 × 500
= 487500 J
Let m1 g be the amount of ice that melts when the copper block is placed on the ice block.
The heat gained by the melted ice, Q = m1L
`:.m_1 =Q/L = 487500/335 = 1455.22 g`
Hence, the maximum amount of ice that can melt is 1.45 kg.
उत्तर २
Here, mass of copper block, m = 2.5 kg = 2500 g
Fall in temperature, `triangle T = 500 - 0= 500^@C`
Specific heat of copper, `c = 0.39 J g^(-1) ""^@C^(-1)`
Latent heat of fusion, `L = 335 J g^(-1)`
Let the mass of ice melted be m'
As, Heat gained by ice = Heat lost by copper
`:. m'L = mc triangle T`
`m' = (mc triangleT)/L`
`m' = (2500xx0.39xx500)/335 =1500 g = 1.5 kg`
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:
CO2 at 1 atm pressure and temperature – 60 °C is compressed isothermally. Does it go through a liquid phase?
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?
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?
The radii of two copper spheres are in the ratio 1 : 3 and their temperatures are in the ratio 9 : 1. The ratio of heat content in them will be:
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.
100 g of water is supercooled to –10°C. At this point, due to some disturbance mechanised or otherwise some of it suddenly freezes to ice. What will be the temperature of the resultant mixture and how much mass would freeze?
`[S_w = 1cal/g/^circC and L_(Fusion)^w = 80cal/g]`
Latent heat of a substance is best defined as ______.
Why does water stay at 100°C while boiling?
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)?
The heating curve below shows temperature vs. heat added for ice, water and steam at 1 atm ______.
