Step-by-step explanation:
To calculate the enthalpy of combustion of glucose, we need to first calculate the amount of heat released by the combustion reaction.
The heat released can be calculated using the formula:
Q = CΔT
where Q is the heat released (in joules), C is the calorimeter constant (in joules per degree Celsius), and ΔT is the change in temperature of the calorimeter (in degrees Celsius).
In this case, we have:
Q = 8000 J/K x (21.14 °C - 19.20 °C) = 16000 J
This is the amount of heat released by the combustion of 1.00 g of glucose.
To calculate the enthalpy of combustion of glucose, we need to convert the amount of heat released to the enthalpy change of the reaction. We can do this using the equation:
ΔH = Q/n
where ΔH is the enthalpy change (in joules per mole), Q is the heat released (in joules), and n is the number of moles of glucose combusted.
The number of moles of glucose can be calculated using its molar mass:
n = mass/molar mass = 1.00 g / 180 g/mol = 0.00556 mol
Now we can calculate the enthalpy of combustion:
ΔH = 16000 J / 0.00556 mol = 2.88 x 10^6 J/mol
To express this in kJ/g, we can divide by the mass of glucose used:
ΔH = 2.88 x 10^6 J/mol / 1.00 g = 2.88 x 10^3 kJ/g
Therefore, the enthalpy of combustion of glucose is 2.88 x 10^3 kJ/g.