need chemistry help for today!! pleasee?

Question

Calculate the mass of methane that must be burned to provide enough heat to convert 299.0 g of water at 28 Celsius into steam at 111 Celsius. (assume that the H2O produced in the combustion reaction is steam rather than liquid water)

Answer 1

First off, you do not have the heat of combustion of methane. When you have that, you will be able to do the rest of the problem.

First, raise the temperature of the water by 78degC to 100C:

299.0gH2O x 78degC x 1cal/g-degC = 23322 cal

Next, boil the water, using the latent heat of vaporization of water:

299.0gH2O x 539.6cal/1gH2O = 161,340 cal

Next, raise the temperature of the steam to 111C. For this, you need the heat capacity of steam. You do not have this. Finally, you add up the calories to raise the temperature of the water, boil the water, and raise the temperature of the steam. You take this total number of calories, plug that into the number of calories given off when a mole of methane burns, and you'll have the mass of methane burned to do all of this.