Q. 3.32 - An Introduction to General, Organic, and Biological Chemistry

Question

Using the energy values for foods (see Table $3.7$), determine each of the following (round off the answer for each food type to the tens place):

$\left(a\right)$ the total kilojoules in two tablespoons of crunchy peanut butter that contains $6 g$ of carbohydrate, $16 g$ of fat, and $7 g$ of protein

$\left(b\right)$the grams of protein in one cup of soup that has $110 kcal$ with $9 g$ of carbohydrate and $6 g$ of fat

$\left(c\right)$the kilocalories in one can of cola if it has $40.0 g$of carbohydrates and no fat or protein

$\left(d\right)$ the total kilocalories for a diet that consists of $68 g$ of carbohydrate, $9 g$ of fat, and $150 g$ of protein

Step-by-Step Solution

Answer

Part $\left(a\right)$The peanut butter energy is $829 kJ.$

Part $\left(b\right)$Protein in one cup of soup is $5 g.$

Part $\left(c\right)$One tin cola energy value is $160 kcal.$

Part $\left(d\right)$The diet energy value is $953 kcal.$

(Part a) Step: 1 Given information:

Given are:  $6 g$ of carbohydrates, $16 g$ of fat, and $7 g$ of protein 

To find the two tablespoons of crunchy peanut butter in kilojoules. 

(Part a) Step: 2 Peanut butter in kilojoules:

Carbohydrate value $17 kJ/g$

Protein value $17 kJ/g$

Fat value $38 kJ/g$

$16 g$ of carbohydrate $=6 \mathrm{g}\times 17 \mathrm{kJ}/\mathrm{g}$ $=102 kJ$

$7 g$ of protein  $=7 \mathrm{g}\times 17 \mathrm{kJ}/\mathrm{g}$ $=119 kJ$

$16 g$ of protein  $=16 \mathrm{g}\times 38 \mathrm{kJ}/\mathrm{g}$ $=608 kJ$

The amount of energy is,

$=102 \mathrm{kJ}+119 \mathrm{kJ}+608 \mathrm{kJ}$

As a result, the sum of two tablespoon of peanut butter is $829 kJ.$

(Part b) Step: 3 Given information:

Given are: $9 g$ of carbohydrate, $6 g$ of fat, and $110 kcal.$

To find the the grams of protein in one cup of soup.

(Part b) Step: 4 Protein in one cup soup:

One cup of soup energy $=110 kcal$

Carbohydrate value $=4 kcal/g$

Fat value $=9 kcal/g$

$9 g$ of carbohydrate value is  $9 \mathrm{g}\times 4 k\mathrm{cal}/\mathrm{g}$ $=36 kcal$

 $6 g$ of fat value is $6 \mathrm{g}\times 9 \mathrm{kcal}/\mathrm{g}$ $=54 kcal$

The total energy is $=(36+54) \mathrm{kcal}$ $=90 kcal$

Fat energy is $=110 \mathrm{kcal}-90 \mathrm{kcal}$ $=20 kcal$

$\text{ Energy of protein }=\text{ energy value of protein }\times \text{ mass }$

$20 \mathrm{kcal}=4 \mathrm{kcal}/\mathrm{g}\times \text{ mass }$$\text{ mass }=\frac{20 \mathrm{kcal}}{4 \mathrm{kcal}/\mathrm{g}}=5 \mathrm{g}$

As a result, protein in one cup of soup is $5 g.$

(Part c) Step: 5 Given information:

Given are: $40 g$ of carbohydrate, no fat and protein.

To find the the kilocalories in one tin of cola.

(Part c) Step: 6 One tin of cola:

Carbohydrate value $= 4 kcal/g$

 $40 g$of carbohydrate value

$=40 \mathrm{g}\times 4 \mathrm{kcal}/\mathrm{g}$

$=160 kcal$

As a result, the one tin of cola is $160 kcal.$

(Part d) Step: 7 Given information:

Given are: $68 g$ of carbohydrate, $9 g$ fat and $150 g$ protein.

To find the diet in kilocalories.

(Part d) Step: 8 Diet in kilocalories:

$68 g$ of carbohydrate value  $=68 \mathrm{g}\times 4 \mathrm{kcal}/\mathrm{g}$ $=272 kcal$

 $9 g$of fat is  $=9 \mathrm{g}\times 9 \mathrm{kcal}/\mathrm{g}$ $=81 kcal$

$150 g$ of protein is  $=150 \mathrm{g}\times 4 \mathrm{kcal}/\mathrm{g}$ $=600 kcal$

The sum of energy is,

$=272 \mathrm{kcal}+81 \mathrm{kcal}+600 \mathrm{kcal}$

$=953 kcal.$

As a result, the diet in kilocalories is $953 kcal.$