1. What is the heat required in kilocalories to convert 2 kg of ice at 0°C completely into steam at 100°C? (I thought it was 2000 kilo cals but I think I'm wrong??)

a. 80 Calories
b. 1440 Calories
c. 4186 Calories
d. 540 Calories

2. A gaseous refrigerant undergoes compression over 160 J of work done on it. If the internal energy of the gas increases by 130 J, the amount of heat transfer is what?

a. 290 J
b.-290 J
c. 30 J
d. -30 J

Thanks SO much!!

1440

To calculate the heat required to convert ice into steam, we need to consider two separate steps:

1. Heating the ice from 0°C to its melting point at 0°C.
2. Melting the ice at 0°C into water at 0°C.
3. Heating the water from 0°C to its boiling point at 100°C.
4. Vaporizing the water at 100°C into steam at 100°C.

Let's calculate the heat required for each step:

Step 1: Heating the ice from 0°C to its melting point at 0°C.
The specific heat capacity of ice is 2.09 J/g°C, and the mass of ice in question is 2 kg.

Heat required = mass × specific heat capacity × temperature change
= 2000 g × 2.09 J/g°C × (0°C - 0°C)
= 0 J

Step 2: Melting the ice at 0°C into water at 0°C.
The heat of fusion (latent heat) for water is 335 J/g.

Heat required = mass × heat of fusion
= 2000 g × 335 J/g
= 670,000 J
= 670 kJ

Step 3: Heating the water from 0°C to its boiling point at 100°C.
The specific heat capacity of water is 4.18 J/g°C.

Heat required = mass × specific heat capacity × temperature change
= 2000 g × 4.18 J/g°C × (100°C - 0°C)
= 836,000 J
= 836 kJ

Step 4: Vaporizing the water at 100°C into steam at 100°C.
The heat of vaporization (latent heat) for water is 2260 J/g.

Heat required = mass × heat of vaporization
= 2000 g × 2260 J/g
= 4,520,000 J
= 4,520 kJ

Total heat required = Step 2 + Step 3 + Step 4
= 670 kJ + 836 kJ + 4,520 kJ
= 6036 kJ

Converting to kilocalories:
1 kilocalorie (kcal) = 4.18 kilojoules (kJ)

Total heat required = 6036 kJ / 4.18 kcal/kJ
≈ 1446 kcal

So, the correct answer for the first question is b) 1440 Calories.

For the second question:
The first law of thermodynamics states that the change in internal energy (ΔU) is equal to the heat transfer (Q) minus the work done on the system (W).

ΔU = Q - W

Given that W = 160 J and ΔU = 130 J, we can rearrange the equation to solve for Q:

Q = ΔU + W
= 130 J + 160 J
= 290 J

Therefore, the correct answer for the second question is a) 290 J.

1. To calculate the heat required to convert ice at 0°C to steam at 100°C, we need to consider three different processes: heating the ice from 0°C to its melting point, melting the ice into liquid water at 0°C, and heating the liquid water from 0°C to 100°C to convert it into steam.

Let's break down the calculations for each step:

1. Heating the ice from 0°C to its melting point:
The specific heat of ice is 2.09 J/g°C, and we have 2 kg of ice. Therefore, the heat required can be calculated as follows:
Heat = (Mass) x (Specific heat) x (Temperature change)
= (2000 g) x (2.09 J/g°C) x (0 - 0°C)
= 0 J

2. Melting the ice into liquid water at 0°C:
The heat of fusion for water is 334 J/g, and we have 2 kg of ice. Therefore, the heat required can be calculated as follows:
Heat = (Mass) x (Heat of fusion)
= (2000 g) x (334 J/g)
= 668,000 J

3. Heating the liquid water from 0°C to 100°C:
The specific heat of liquid water is 4.18 J/g°C, and we have 2 kg of water. Therefore, the heat required can be calculated as follows:
Heat = (Mass) x (Specific heat) x (Temperature change)
= (2000 g) x (4.18 J/g°C) x (100 - 0°C)
= 836,000 J

Now, to convert the total heat from joules to kilocalories, we divide by 4184 J/kcal:
Total Heat = (0 J + 668,000 J + 836,000 J) / 4184 J/kcal
= 1504 kcal (approx)

Therefore, the correct answer is not 2000 kilocalories, but approximately 1504 kilocalories. None of the answer choices provided match this value, so the correct answer is not listed.

2. The amount of heat transfer can be calculated using the first law of thermodynamics, which states that the change in internal energy of a system is equal to the heat added to the system minus the work done by the system.

Mathematically, it can be expressed as:
Change in Internal Energy = Heat Added - Work Done

Given that the internal energy of the gas increases by 130 J and the work done on the gas is 160 J, we can calculate the amount of heat transfer as follows:
Heat Added = Change in Internal Energy + Work Done
= 130 J + 160 J
= 290 J

Therefore, the correct answer is a. 290 J.