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# An average person needs about 10000 kJ energy per day.

Question:

An average person needs about $10000 \mathrm{~kJ}$ energy per day. The amount of glucose (molar mass $=180.0 \mathrm{~g} \mathrm{~mol}^{-1}$ ) needed to meet this energy requirement is _________g.

(Use : $\Delta_{\mathrm{C}} \mathrm{H}$ (glucose) $=-2700 \mathrm{~kJ} \mathrm{~mol}^{-1}$ )

Solution:

1 mole glucose give 2700 kJ energy

so mole of glucose needed for $10^{5} \mathrm{~kJ}$ energy

$=\frac{10000}{2700}=370 \mathrm{moles}$

wt. of glucose $=3.10 \times 180$

$=666.666$

$\approx 667 \mathrm{gm}$

$\frac{Y_{\text {Benzene }}}{Y_{\mathrm{M} . \mathrm{B}}}=\frac{\mathrm{P}_{\mathrm{B}}^{0} \mathrm{X}_{\mathrm{B}}}{\mathrm{P}_{\mathrm{MB}}^{0} \mathrm{X}_{\mathrm{MB}}}=\frac{70 \times 1}{20 \times 1}=\frac{7}{2}$

$Y_{\text {Benzene }}=\frac{7}{9}=77.77 \times 10^{-2}$

$=78 \times 10^{-12}$