Question

4.The molar enthalpy of combustion of glucose, C6H12O6(s) is –2538.7 kJ/mol.What mass of glucose is needed to produce - 3750 kJ of energy?

Answer 1

265.9 g of glucose.

Step-by-step explanation:

What is given?

Molar enthalpy of glucose = -2538.7 kJ/mol.

Amount of energy of glucose = -3750 kJ.

Molar mass of glucose (C6H12O6) = 180 g/mol (you can calculate this using the periodic table).

Step-by-step solution:

First, we have to find the number of moles of glucose by doing a dimensional analysis of the given data. The molar enthalpy is telling us that the change of energy of 1 mol of glucose is -2538.7 kJ, so the dimensional analysis will look like this:

`-3750\text{ kJ}\cdot\frac{1\text{ mol glucose}}{-2538.7\text{ kJ}}=1.477\text{ moles glucose.}`

And the final step is to convert from 1.477 moles of glucose to grams using its molar mass. The conversion would be:

`1.477\text{ moles glucose}\cdot\frac{180\text{ g glucose}}{1\text{ mol glucose}}=265.9\text{ g glucose.}`

The answer is that the mass of glucose needed to produce -3750 kJ of energy is 265.9 g.