Calorimeter

Q.

A copper ball of mass $100gm$ is at a temperature $T$. It is dropped in a copper calorimeter of mass $100gm$, filled with $170gm$ of water at room temperature. Subsequently, the temperature of the system is found to be $75°C$. $T$ is given by : (Given : room temperature $=30°C$, specific heat of copper $=0.1cal/gm°C$)

1. $800°C$

2. $885°C$

3. $1250°C$

4. $825°C$

Q.

Calculate the amount of ice that is required to cool 150 g of water contained in a vessel of mass of 100 g at $30°\mathrm{C}$, such that the final temperature of the mixture is $5°\mathrm{C}$. Take specific heat capacity of material of vessel as $0.4\mathrm{J}\mathrm{g}°{\mathrm{C}}^{-1}$; specific latent heat of fusion of ice is $336\mathrm{J}{\mathrm{g}}^{-1}$; specific heat capacity of water is $4.2\mathrm{J}{\mathrm{g}}^{-1}°{\mathrm{C}}^{-1}$

Q.

How do you increase the rate of cooling?

Q.

The calorimeter is commonly made up of……..because it has…….

Q.

A platinum sphere floats in mercury. Find the percentage change in the fraction of volume of sphere immersed in mercury when the temperature is raised by ${80}^{\circ }C$ (Volume expansivity of mercury is $182\times {10}^{-6}{/}^{\circ }C$ and linear expansivity of platinum is $9\times {10}^{-6}{/}^{\circ }C$)

1. 1.24%

2. 1.38%

3. 2.48%

4. 2.76%

Q. Calculate the heat required to heat $0.5kg$ of water from $20{}^{\circ }C$ to $70{}^{\circ }C$. If the specific heat of water is $4200\frac{J}{kg.K}$.

Q.

Two identical calorimeters A and B contain an equal quantity of water at 20^oC. A 5g piece of metal X of specific heat 0.2 cal g^-1o C^-1 is dropped into A and a 5g piece of metal Y into B. The equilibrium temperature in A is 22^o C and in B is 23^o C. The initial temperature of both the metals is 40^o C. Find the specific heat of metal Y in cal g^-1oC^-1.

1. $\frac{27}{85}\raisebox{1ex}{$cal$}\!\left/ \!\raisebox{-1ex}{$g°C$}\right.$

2. $26\raisebox{1ex}{$cal$}\!\left/ \!\raisebox{-1ex}{$g°C$}\right.$

3. $\frac{85}{27}\raisebox{1ex}{$cal$}\!\left/ \!\raisebox{-1ex}{$g°C$}\right.$

4. $27\raisebox{1ex}{$cal$}\!\left/ \!\raisebox{-1ex}{$g°C$}\right.$

Q. A layer of ice of thickness y is on the surface of a lake. The air is at a constant temperature $-{\theta }^{\circ }C$ and the ice water interface is at $0^{\circ }$. Then that the rate at which the thickness increases is given by.
$\frac{dy}{dt}=\frac{k\theta }{L\rho y}$
where k is the thermal conductivity of the ice, L the latent heat of fusion and $\rho$ is the density of the ice.Type 1 for true and 0 for false

Q.

Which of the two has more heat $1\mathrm{g}$ water at ${100}^{\circ }\mathrm{C}$ or $1\mathrm{g}$ steam at ${100}^{\circ }\mathrm{C}$? Give reason.

Q.

The vibrations of the molecules in a solid become weaker as the temperature rises.

1. True
2. False

Q.

The average temperature of the human body 37 °C. What will it be in °F?

1. 99 °F

2. 100 °F

3. 98 °F

4. 98.6 °F

Q. When 1 kg of ice $0^{\circ }C$ melts to water $0^{\circ }C$, the resulting change in its entropy , taking latent heat of ice to be 80 Cal/gm is-

1. $80Cal/K$
2. $293Cal/K$
3. $273Cal/K$
4. ${8\times 10}^4$ Cal/K

Q. If $10$ gram of ice at $0^{\circ }C$ is mixed with $10$ gram of water at ${40}^{\circ }C$. The final mass of water in mixture is
(Latent heat of fusion of ice $=80cal/gm$; specific heat of water $=1cal/g{m}^{\circ }C$)

1. 10 gram
2. 15 gram
3. 18 gram
4. 20 gram

Q.

The energy required to raise a given volume of water from a well can be in

1. megawatts

2. meganewton

3. megajoules

4. kilowatts

Q. If water of mass 20 g at $0{}^{o}C$ is mixed with 40 g of water at $10{}^{o}C$, then the final temperature of the mixture is $10{}^{o}C$

1. True
2. False

Q. 15 g ice at $0^{\circ }C$ is mixed with 10 g water and ice in the mixture. final temperature will be in ${}^{o}C$?

Q.

Match the following

Column 1	Column 2
Boiling point of pure water	100$°$C
Temperature of maximum density of water	4$°$C
Latent heat of fusion	336 J/g
Aerated water	Water containing dissolved carbon dioxide

Q. Two identical bodies are made of a material for which the heat capacity increases with temperature. One of these is held at a temperature of $100$ while the other one is kept at $0$. If the two are brought into contact, then, assuming no heat loss to the environment, the final temperature that they will reach is :

1. More than $50$
2. $0$
3. $50$
4. Less than $50$

Q. Indian style of cooling drinking water is to keep it in a pitcher having porous walls. Water comes to the outer surface very slowly and evaporates. Most of the energy needed for is taken from the water itself and the water is cooled down. Assume that a pitcher contains $10kg$ of water and $0.2g$ of water comes out per second. Assuming no backward heat transfer from the atmosphere to the water, calculate the time in which the temperature decreases by $5^{o}C$. Specific heat capacity of water ${=4200J{kg}^{-1}}^{}{C}^{-1}$ and latent heat of vaporization of water $=2\cdot 27\times {10}^{6}J{kg}^{-1}$.

Q. Water of volume $2L$ in a container is heated with a coil of $1kW$ at ${27}^o$C. The lid of the container is open and energy dissipates at rate of $160$ J/s. In how much time temperature will rise from ${27}^o$C to ${77}^o$C?[Given specific heat of water is $4.2$kJ/kg]

1. 7 min
2. 8 min 20 s
3. 6 min 2 s
4. 14 min

Q. A calorimeter of mass $50g$ and specific heat capacity $0.42J{g}^{-1}{℃}^{-1}$ contains some mass of water at ${20}^{o}C$. A metal piece of mass $20g$ at ${100}^{o}C$ is dropped into the calorimeter. After stirring, the final temperature of the mixture is found to be ${22}^{o}C$. Find the mass of water used in the calorimeter.
[specific heat capacity of the metal piece $=0.3J{g}^{-1}{℃}^{-1}$
specific heat capacity of water $=4.2J{g}^{-1}{℃}^{-1}$]

Q. When $100$g of a liquid A at ${100}^o$C is added to $50$g of a liquid B at temperature ${75}^o$C, the temperature of the mixture becomes ${90}^o$C. The temperature of the mixture, if $100$g of liquid A at ${100}^o$C is added to $50$g of liquid B at ${50}^o$C, will be?

1. ${80}^o$C
2. ${70}^o$C
3. ${85}^o$C
4. ${60}^o$C

Q. A solid whose volume does not change with temperature floats in a liquid. For two different temperatures $t_1$ and $t_2$ of the liquid, fractions $f_1$ and $f_2$ of the volume of the solid remain submerged in the liquid. The coefficient of volume expansion of the liquid is equal to

1. 
2. 
3. 
4. 

Q. How much steam at ${100}^o$C will just melt $2700$g of ice at $-{10}^o$C. (Sp. heat of ice $=0.5$ and latent heat of steam $=540$ cal $g^{-1}$)

Q. $1g$ of steam at ${100}^{o}C$ and equal mass of ice at $0^{o}C$ are mixed. The temperature of the mixture in steady state will be (latent heat of steam $=540cal/g$, latent heat of ice $=80cal/g$

1. ${50}^{o}C$
2. ${100}^{o}C$
3. ${67}^{o}C$
4. ${33}^{o}C$

Q. A copper vessel of mass 100g contains 150g of water at ${50}^{o}C$. How much ice is needed to cool it to $5^{o}C$?
Given: Specific heat capacity of copper $=0.4J{g}^{-1}$ ${}^o{C}^{-1}$
Specific heat capacity of water $=4.2J{g}^{-1}$ ${}^o{C}^{-1}$
Specific latent heat of fusion of ice $=336J{g}^{-1}$

Q. Calculate the mass of steam at ${100}^{\circ }C$ needed to just melt 320 g of ice at $-{10}^{\circ }C$. The specific heat of ice $=0.5cal{g}^{-1}{}^{\circ }{C}^{-1}$, latent heat of vaporization of steam $=540cal{g}^{-1},$ specific heat of fusion of ice $=80cal{g}^{-1}$.

Q. A cup of tea cools from ${80}^{o}C$ to ${60}^{o}C$ in one minute. The ambient temperature is ${30}^{o}C$. In cooling from ${60}^{o}C$ to ${50}^{o}C$, it will take :

1. $50sec$.
2. $90sec$
3. $60sec$.
4. $48sec$.

Q. A copper block of mass $2kg$ is heated to temperature of ${500}^{\circ }C$ and then placed in a large block of ice at $0^{\circ }C$. What is the maximum amount of ice that can melt? The specific heat of copper is 400 J ${kg}^{-1}$ ${}^{\circ }{C}^{-1}$ and latent heat of fusion of water is $3.5\times {10}^{5}J$ ${kg}^{-1}$ .

Q. Q9. Explain the time-temperature graph of water depicted below? [3 marks]​