How much heat energy is needed to change 0.25kg of water at 100°C to steam at 100°C? Show your work.
Please don't give me the answer, I just need help figuring out how to find the answer. Thanks!
look up the heat of vaporization for steam.
heat=mass*heatvaporizaiton
To find the amount of heat energy needed to change 0.25kg of water at 100°C to steam at 100°C, we can use the concept of specific heat capacity and latent heat.
Step 1: Calculate the heat energy required to raise the temperature of water from 100°C to its boiling point (100°C):
- The specific heat capacity of water is approximately 4.18 J/g°C.
- First, convert the mass from kg to grams: 0.25 kg = 250 g.
- Use the formula: Q = m * c * ΔT, where Q is the heat energy, m is the mass, c is the specific heat capacity, and ΔT is the temperature change.
- ΔT = (100°C - 100°C) = 0°C (as the temperature is constant).
- Therefore, Q = 250 g * 4.18 J/g°C * 0°C = 0 J.
Step 2: Calculate the heat energy required for vaporization (latent heat):
- The latent heat of vaporization of water is approximately 2260 J/g.
- Use the formula: Q = m * L, where Q is the heat energy, m is the mass, and L is the latent heat.
- Q = 250 g * 2260 J/g = 565,000 J.
Step 3: Add the heat energy required for both steps:
- Q_total = Q1 + Q2 = 0 J + 565,000 J = 565,000 J.
Therefore, the amount of heat energy needed to change 0.25kg of water at 100°C to steam at 100°C is 565,000 Joules (J).
To find the amount of heat energy needed to change a substance from one phase to another, you need to consider the specific heat capacity and latent heat of the substance. In this case, we need to determine the heat energy required to change 0.25kg of water at 100°C to steam at 100°C.
Here is the step-by-step process to calculate it:
1. Determine the heat energy required to raise the temperature of 0.25kg of water from 100°C to its boiling point, which is 100°C.
- The specific heat capacity of water is approximately 4.18 J/g°C, which means it takes 4.18 Joules of heat energy to raise the temperature of 1 gram of water by 1 degree Celsius.
- Convert the mass from kg to grams. In this case, multiply 0.25kg by 1000 to get 250 grams.
- Use the formula: heat energy = mass × specific heat capacity × temperature change.
- Calculate the heat energy required to raise the temperature from 100°C to the boiling point (100°C).
heat energy = 250g × 4.18 J/g°C × (100°C - 100°C).
This calculation will give you 0 Joules since there is no temperature change.
2. Determine the heat energy required to change water at its boiling point (100°C) to steam at the same temperature.
- The latent heat of vaporization (also known as the heat of vaporization) for water is approximately 2260 J/g.
- Use the formula: heat energy = mass × latent heat of vaporization.
- Calculate the heat energy required to change 0.25kg (250 grams) of water at 100°C to steam at 100°C.
heat energy = 250g × 2260 J/g.
This calculation will give you the heat energy required in Joules.
By following these steps and plugging in the appropriate values, you will be able to find the amount of heat energy needed to change the water to steam at 100°C.