Find the amount of heat require to change ice at - 20c to steam at 120c. The mass of the ice is 5 kg
To find the amount of heat required to change ice at -20°C to steam at 120°C, we need to calculate the heat required for each phase transition and the heat required for the temperature change within a phase.
First, let's break down the process into three stages:
1. Heating the ice from -20°C to 0°C.
2. Melting the ice at 0°C.
3. Heating the water from 0°C to 100°C, then converting it into steam at 100°C and heating the steam to 120°C.
To calculate the amount of heat required for each stage, we will use the specific heat capacity and latent heat values. Here are the values we need:
- Specific heat capacity of ice (cice) = 2.09 J/g°C
- Specific heat capacity of water (cwater) = 4.18 J/g°C
- Specific heat capacity of steam (csteam) = 2.03 J/g°C
- Latent heat of fusion (Lfusion) = 334 J/g
- Latent heat of vaporization (Lvaporization) = 2260 J/g
Now let's calculate the heat required for each stage:
1. Heating the ice from -20°C to 0°C:
Q1 = mass × cice × temperature change
Q1 = 5 kg × 2.09 J/g°C × (0°C - (-20°C))
Q1 = 5 kg × 2.09 J/g°C × 20°C
Q1 = 209 J/g × 5 kg × 20°C
Q1 = 20900 J
2. Melting the ice at 0°C:
Q2 = mass × Lfusion
Q2 = 5 kg × 334 J/g
Q2 = 5 kg × 334000 J
Q2 = 1670000 J
3. Heating the water from 0°C to 100°C, converting it into steam at 100°C, and heating the steam to 120°C:
Q3 = mass × cwater × temperature change + mass × Lvaporization + mass × csteam × temperature change
Q3 = 5 kg × 4.18 J/g°C × (100°C - 0°C) + 5 kg × 2260 J/g + 5 kg × 2.03 J/g°C × (120°C - 100°C)
Q3 = 5 kg × 4.18 J/g°C × 100°C + 5 kg × 2260 J/g + 5 kg × 2.03 J/g°C × 20°C
Q3 = 2090 J/g × 5 kg × 100°C + 11300 J/g × 5 kg + 40.6 J/g × 5 kg × 20°C
Q3 = 1045000 J + 56500 J + 4080 J
Q3 = 1103580 J
Finally, to find the total amount of heat required:
Total heat = Q1 + Q2 + Q3
Total heat = 20900 J + 1670000 J + 1103580 J
Total heat = 2790080 J
Therefore, the amount of heat required to change the ice at -20°C to steam at 120°C with a mass of 5 kg is 2,790,080 Joules.
there are five "stages"
heat ice to 0º
melt ice
heat water to 100º
boil water
heat steam
you will need the specific heats of ice, water, and steam