The combustion of 1.00 mol of sucrose,C12H22,O11, evolves 5650 kJ of heat. A bomb calorimeter has a calibrated heat capacity of 1.23 kj/degree Celsius. How many grams of sucrose should be burned to raise the temperature of the calorimeter and its contents from 23 degrees C to 80 degrees C?

Question

The combustion of 1.00 mol of sucrose,C12H22,O11, evolves 5650 kJ of heat. A bomb calorimeter has a calibrated heat capacity of 1.23 kj/degree Celsius. How many grams of sucrose should be burned to raise the temperature of the calorimeter and its contents from 23 degrees C to 80 degrees C?

Answer 1

How much heat is need to raise the T of the calorimeter and its contents from 23 to 80 C?

1.23 kJ/oC x (80-23) = 70.11 kJ.
So burning 1 mole sucrose (342 grams is it--check me out on that) produces 5650 kJ.
342 g x (70.11/5650) = ?? g sucrose. Check my thinking.

Answer 2

To solve this problem, we need to calculate the amount of heat required to raise the temperature of the calorimeter and its contents from 23°C to 80°C and then determine the mass of sucrose needed to produce this amount of heat.

First, let's calculate the heat required using the formula:

q = mcΔT

where:
q = heat (in kJ)
m = mass (in grams) of the calorimeter and its contents
c = heat capacity of the calorimeter (in kJ/°C)
ΔT = change in temperature (in °C)

We are given:
m = ?
c = 1.23 kJ/°C
ΔT = 80°C - 23°C = 57°C

Substituting the given values into the formula, we get:

q = mcΔT
q = (m)(1.23)(57)

Now, we know that the combustion of 1.00 mol of sucrose releases 5650 kJ of heat. Therefore, the heat produced by burning 'n' moles of sucrose can be calculated using the proportion:

5650 kJ / 1 mol = q / n mol

Since we want to find the mass of sucrose (in grams) needed to produce 'q' kJ of heat, using the molar mass of sucrose, we have:

1 mol of sucrose = 342.3 g

Therefore, we can set up the following equation:

5650 kJ / 1 mol = (q / n mol) * (342.3 g / 1 mol)

Now, we have two equations related to 'q' and 'n':

q = (m)(1.23)(57)
5650 kJ / 1 mol = (q / n mol) * (342.3 g / 1 mol)

By equating them, we can solve for 'm':

(m)(1.23)(57) = (5650 / n) * (342.3)

Simplifying the equation and solving for 'm', we get:

m = (5650 / n) * (342.3) / (1.23)(57)

Thus, the formula to calculate the mass of sucrose needed is:

m = (5650 * 342.3) / (n * 1.23 * 57)

Now, substitute the given value for the heat evolved during combustion (5650 kJ) and solve for 'm' when the temperature change requires raising the temperature from 23°C to 80°C.