41. How much heat energy must you use to raise the temperature of 100 grams of water from 60C to 70C. Show your calculations.
42. You have a pot of 100C liquid water. If you add heat to the water, will the temperature start to raise at once? why or why not.
Thank you for your help!!
41. q = mass H2O x specific heat H2O x (Tfinal-Tinitial)
42. 100 C is the boiling point for H2O. If you add more heat to water at 100 C it will start to boil. It will continue to boil until all of the water has evaporated. The temperature of the pot will not go above 100 C until all of the water has evaporated.
41. To calculate the amount of heat energy needed to raise the temperature of a substance, we can use the specific heat capacity formula:
Q = m * c * ΔT
Where:
Q = amount of heat energy
m = mass of the substance (in grams)
c = specific heat capacity of the substance (in J/g°C)
ΔT = change in temperature (final temperature - initial temperature)
In this case, we are given:
m = 100 grams (mass of water)
ΔT = 70°C - 60°C = 10°C (change in temperature)
c = 4.18 J/g°C (specific heat capacity of water)
Using the formula, we can calculate the amount of heat energy required:
Q = 100 g * 4.18 J/g°C * 10°C
Q = 4180 J
Therefore, you would need 4180 joules of heat energy to raise the temperature of 100 grams of water from 60°C to 70°C.
42. No, the temperature will not start to raise immediately when heat is added to the water. This is because water has a high specific heat capacity, which means it requires a significant amount of heat energy to raise its temperature.
When heat is added to the water, it first goes through a process called phase change, where the water absorbs heat energy to change from a liquid to a gas. This phase change occurs at 100°C and is known as the boiling point.
During this phase change, the water is absorbing the heat energy, but its temperature remains constant at 100°C until all of the water has vaporized. This is because the heat energy is being utilized to break the bonds between water molecules and convert them into a gas, rather than increasing the temperature of the water.
Once all the water has vaporized, any additional heat energy will start to raise the temperature of the gas (steam). Therefore, the temperature will not start to rise immediately when heat is added to the water, but rather during and after the phase change.