Question

1.200g of water heated from 17.0 degrees Celsius to 23.5 degrees Celsius . What is the amount of thermal energy that been transferred to that mass?

2. beaker contains 360.4g of whiten the liquid state at 100 degrees Celsius . How much energy in KJ is required to convert the liquid water to water vapours?

3. what is the amount of heat energy required to change a 40.0g ice cube at -20.0 degrees Celsius to water at 50.0 degrees Celsius ?

4.500g mass of copper at 15.0 degrees Celsius, copper gains 650 joules of thermal energy. What would be final temperature of that mass? ( c=0.386 j/g degrees Celsius)

Answer 1

Answer on Question #52984, Physics / Molecular Physics | Thermodynamics

1. 200g of water heated from 17.0 degrees Celsius to 23.5 degrees Celsius. What is the amount of thermal energy that been transferred to that mass?

Solution

$$Q = mc\Delta t = 0.2 \times 4.187 \times (23.5 - 17) = 5.4431\ KJ$$

Answer: 5.4431 KJ.

2. Beaker contains 360.4g of white the liquid state at 100 degrees Celsius. How much energy in KJ is required to convert the liquid water to water vapours?

Solution

$$Q = Lm = 2256 \times 0.3604 = 813.0624\ KJ$$

Answer: 813.0624 KJ.

3. what is the amount of heat energy required to change a 40.0g ice cube at -20.0 degrees Celsius to water at 50.0 degrees Celsius?

Solution

If melting point of ice $T=0{}^{\circ}C$

$$Q = Q_1 + Q_2 + Q_3; \quad Q_1 = mc_{ice}\Delta t = 0.04 \times 2060 \times 20 = 1648\ J;$$ $$Q_2 = \lambda m = 335000 \times 0.04 = 13400\ J; \quad Q_3 = mc_{water}\Delta t = 0.04 \times 4187 \times 50 = 8374\ J;$$ $$Q = 1648 + 13400 + 8374 = 23422\ J$$

Answer: 23422 J

4. 500g mass of copper at 15.0 degrees Celsius, copper gains 650 joules of thermal energy. What would be final temperature of that mass? (c=0.386 j/g degrees Celsius)

Solution

$$Q = mc\Delta t = mc(t_2 - t_1); \quad t_2 = \frac{Q}{mc} + t_1;$$ $$t_2 = \frac{650}{500 \times 0.386} + 15 = 18.368\ {}^{\circ}\mathrm{C}$$

Answer: 18.368 °C

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