# chemistry

how many kilocalories of heat are released when 85g steam at 100 degrees C converted to ice at 0.

1. 👍 0
2. 👎 0
3. 👁 373
1. Three steps are involved: steam changing to water at 100 C; water at 100 C cooling to 0 C; water at 0 C freezing to ice at 0 C.
Steam changing to water:
Heat of vaporization of water is 539.4 cal/g
Heat = Heat of Vap. x mass = 539.4 cal/g x 75.0 g = 40,500 cal
Cooling water from 100 C to 0 C:
Heat = mass x specific heat x T change
Heat = 75.0 g x 1.00 cal/gC x 100 C = 7500 cal
Freezing of water at 0 C:
The heat of fusion of water is 79.7 cal/g
Heat = heat of fusion x mass = 79.7 cal/g x 75.0 g = 5980 cal
Total heat = 40,500 + 7500 + 5980 = 53980 cal or 5.40 x 10^4 cal (3 sig figs) = 54.0 kcal

1. 👍 0
2. 👎 0
2. The work above is correct except the process is a bit confusing and hard to follow. I teach this process to my Honors Chemistry students in a similar way, just try to start with your grams and use factor labeling for the easiest way to solve.

1. 👍 0
2. 👎 0

## Similar Questions

1. ### Physics

What is the heat required in kilocalories to convert 2 kg of ice at 0°C completely into steam at 100°C? -80 Calories -1440 Calories -4186 Calories -540 Calories Thanks!

2. ### Physics

A physicist converted 2 kg of water at 37 degrees celcius to steam at 100 degrees celcius. Assuming no heat is lost, calculate the amount of energy needed to heat to 100 degrees celcius.

3. ### chemistry

the heat of vaporization for water is 540 cal/g. how many kilocalories are needed to change 22g of liquid water to steam at 100*c?

4. ### Chemistry

Given that the specific heat capacities of ice and steam are 2.06 J/g degrees C and 2.03 J/g degrees C, respectively, calculate the total quantity of heat evolved when 10.0 g of steam at 200 degrees C is condensed, cooled, and

1. ### chemistry

How much heat (in kilocalories) is released when 7.87g of Al is used in the reaction?

2. ### science

How much heat is absorbed when 52.3 g H2O(l) at 100°C and 101.3 kPa is converted to steam at 100°C? (The molar heat of vaporization of water is 40.7 kJ/mol.)

3. ### Chemistry

How much heat (in kJ) is evolved in converting 1.00 mol of steam at 145.0 degrees C to ice at -45.0 degrees C? The heat capacity of steam is 2.01 J/g* degrees C and of ice is 2.09 J/g*degrees C .

4. ### Physics- Help!!

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

1. ### Thermodynamics

Consider 100 kg/s of steam expanding in a turbine. The inlet to the turbine is at 15 MPa, 500 degrees C. The steam expands to 0.01 MPa. The exit entropy is 6.200 kJ/(kg.K). Though the turbine is well insulated, at a place where

2. ### Chemistry

1. How much heat is absorbed when 63.7g H(small 2)O [water](l) at 100 degrees C and 101.3 kPa is converted to steam at 100 degrees C? Express your answer in kJ. Is there an equation? 2.How much heat (in kJ) is released when 0.677

3. ### chemistry

If 5.00 g of steam (H2O)(g) at 100 C condenses to liquid water (H2O)(l) that is cooled to 50.0 C, how much heat is leberated in calories and kilocalories?

4. ### Chemistry

What is the heat required in Joules to raise the temperature of 100.0g ice at -20 degrees C to steam at 120 degrees C?