The enthalpy of combustion of glucose (mol. Wt. : `180g"mol"^(-1)`) is `-2840kJ"mol"^(-1)`. Then the amount of heat envolved when 0.9 g of glucose is burnt, will be

Options

A. `14.2kJ`
B. `142KJ`
C. `28.4kJ`
D. 1420 KJ

Answer

C

Explanation

The enthalpy of combustion of glucose (mol. Wt. = 180 g / mol) = -2840 kJ / mol
180 g glucose gives enthalpy of combustion = 2840 kJ / mol
1g glucose gives enthalpy of combustion = `2840/(180)`
So, 0.9 g glucose gives enthalpy of combustion
`=2840/(180)xx0.9`
`=2840/(200)kJ=14.2kJ`