Question

1. Calculate the amount of heat (q) produced by the combustion of 4.05 g CH4 (ΔHcomb = -890.4 kJ/mol).

2. Construct a table listing all the data and values you will need to record or find to calculate the specific heat of a single Vienna sausage. Be sure to indicate whether you will need to measure these values or find them from another source. Also make sure you leave enough space for recording these values (with units!) (HINT: Remember q = mcΔT...what do each of these variables stand for? How do you find ΔT?)

3. Recall the 4.05 g methane combusted in Question 1. Assuming all of the heat from this combustion is absorbed by 1.0 kg of 20. ºC water (ignore the pot holding the water, and use 4.18 J g^-1 ºC^-1 for the specific heat of the water). What would be the final temperature of the water? This question can be answered in a few steps.

     a.) First, rearrange equation 3 to solve for ΔT. Show your rearrangement of equation 3 below.

     b.) Now, plug into your equation the values for q, m, and c to find ΔT (be mindful of your kJ and J units).

     c.) Finally, knowing ΔT and the initial temperature, T_I, find the final temperature, T_F, of the water.

Answer 1

Ans 1 :

Molar mass of CH4 is 16.04 g/mol

4.05 g CH4 = 4.05 / 16.04 = 0.25 moles

Enthalpy of combustion for CH4 is -890.4 KJ/mol

So the enthalpy of combustion for 4.05 g CH4 will be :

=0.25 x -890.4

= -222.6 KJ