If you burn 0.200 g of C(graphite) in an excess of O2 to give CO2, the temperature of the calorimeter, which contains 775 g water, increases from 25.00 degrees C to 27.38 degrees C. The heat capacity of the bomb is 893 J/K. What quantity of heat is evolved per mole of C?
C (graphite) + O2 yields CO2
q = (massH2O x specific heat H2O x delta T) + (893*delta T) = ?
Then ?/0.200 = heat/gram
and (heat/gram) x 12 = heat/mol
To calculate the quantity of heat evolved per mole of C (graphite), you can use the information given and follow the steps below:
Step 1: Calculate the heat absorbed by the water.
The heat absorbed by the water can be determined using the formula:
q = m × c × ΔT
Where:
- q is the heat absorbed by the water (in J)
- m is the mass of the water (in g)
- c is the specific heat capacity of water (4.18 J/g°C)
- ΔT is the change in temperature of the water (in °C)
In this case, the mass of water (m) is given as 775 g, the specific heat capacity of water (c) is 4.18 J/g°C, and the change in temperature (ΔT) is 27.38°C - 25.00°C = 2.38°C.
Substituting the given values into the formula:
q = 775 g × 4.18 J/g°C × 2.38°C
q ≈ 7,672.81 J
Step 2: Calculate the moles of C (graphite).
To calculate the moles of C (graphite), you need to use its molar mass. The molar mass of carbon is 12.01 g/mol.
Given that the mass of C (graphite) burned is 0.200 g:
moles of C = 0.200 g / 12.01 g/mol ≈ 0.0167 mol
Step 3: Calculate the heat evolved per mole of C (graphite).
The heat evolved per mole of C (graphite) can be determined by dividing the heat absorbed by the water by the moles of C (graphite) burned.
Heat evolved per mole of C = q / moles of C
Substituting the respective values:
Heat evolved per mole of C ≈ 7,672.81 J / 0.0167 mol
Heat evolved per mole of C ≈ 460,047 J/mol
Therefore, approximately 460,047 J/mol of heat is evolved per mole of C (graphite) burned.