Question

1. 50 grams of water at an initial temperature of 54°C and 110 grams of water at an initial

temperature of 20°C are mixed. What is the final temperature?
2. How much heat must be added to 900 grams of water at 100°C to make it steam at
100°C?

Answer 1

To find the final temperature when two quantities of water at different temperatures are mixed, we can use the principle of conservation of energy. The amount of heat required to convert water at 100°C into steam at 100°C can be calculated using the formula Q = m * L.

Step-by-step explanation:

To find the final temperature when two quantities of water at different temperatures are mixed, we can use the principle of conservation of energy which states that heat lost by hot water equals heat gained by cold water. Let's calculate it step by step:

1. Calculate the heat gained by the cold water using the formula: Q = m * c * ΔT, where Q is the heat gained, m is the mass of the cold water, c is the specific heat capacity of water, and ΔT is the change in temperature.
2. Calculate the heat lost by the hot water using the same formula, but with the mass and initial temperature of the hot water.
3. Since the principle of conservation of energy tells us that the heat gained and heat lost are equal, we can equate the two equations and solve for the final temperature, which will be the same for both quantities of water.

In the second question, to find the amount of heat necessary to convert the water at 100°C into steam at 100°C, we need to use the formula Q = m * L, where Q is the heat required, m is the mass of the water, and L is the latent heat of vaporization for water.

Learn more about calculating final temperature and heat transfer in water mixing and phase changes