Q. 3.36 - An Introduction to General, Organic, and Biological Chemistry

Question

A high-protein diet contains $70.0 g$ of carbohydrate, $5.0 g$ of fat, and $150 g$ of protein. How much energy, in kilocalories and kilojoules, does this diet provide? (Round off the answer for each food type to the tens place.)

Step-by-Step Solution

Answer

The amount of energy is $3900kJ$ and amount of energy in diet is $900 kcal.$

Step: 1 Given information:

Given are:$70g$ of carbohydrate, $5g$ of fat, and $150g$ of protein.

To find the amount of energy in diet.

Step: 2 Amount of energy:

Calculating energy into kilojoules in protein and carbohydrates as

$1 g=17 kJ$

$\frac{1\mathrm{g}}{17\mathrm{kJ}};\frac{17\mathrm{kJ}}{1\mathrm{g}}$

From the table,the fat energy value as

$1 g=38 kJ$

$\frac{1\mathrm{g}}{38\mathrm{kJ}};\frac{38\mathrm{kJ}}{1\mathrm{g}}$

Calculating amount of energy as

$\text{ Energy }=\left(70g\times \frac{17\mathrm{kJ}}{1gg}\right)+\left(150\mathrm{g}\times \frac{17\mathrm{kJ}}{1g\mathrm{g}}\right)+\left(5.0\mathrm{g}\times \frac{38\mathrm{kJ}}{1g\mathrm{g}}\right)$

$Energy=3900kJ.$

Step: 3 Amount of energy in diet:

The diet enrgy in kilocalories as

$1 g=4 kcal/g$

Fats as

$1 g=9 kcal$

$\frac{1\mathrm{g}}{9\mathrm{kcal}};\frac{9\mathrm{kcal}}{1\mathrm{g}}$

The energy amount as 

$\text{ Energy }=\left(70g\times \frac{4\mathrm{kcal}}{1g}\right)+\left(5.0g\times \frac{9\mathrm{kcal}}{1g}\right)+\left(150g\times \frac{4\mathrm{kcal}}{1g}\right)$

As a result,the energy in diet as $900 kcal.$