Q. 3.31 - An Introduction to General, Organic, and Biological Chemistry

Question

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

(a) the total kilojoules for one cup of orange juice that contains 26 g of carbohydrate, no fat, and $2 g$of protein

(b) the grams of carbohydrate in one apple if the apple has no fat and no protein and provides $72 kcal$of energy

(c) the kilocalories in one tablespoon of vegetable oil, which contains $14 g$of fat and no carbohydrate or protein

(d )the grams of fat in one avocado that has $405 kcal$, $13 g$ of carbohydrate, and $5 g$ of protein

Step-by-Step Solution

Answer

Part (a) The orange juice total energy is $476 kJ.$

Part (b) One apple in carbohydrates is $18 g.$

Part (c) Teaspoon of vegetable oil energy is $126 kcal.$

Part (d) One avocado fat is $37 g.$

(Part a) Step1: Given information .

Given data are:$26 g$of carbohydrates, no fat and $2 g$ of protein

To find the one cup of orange juice in kilojoules.

(part a) Step2: orange juice total energy .

The energy values are

Carbohydrate is $17 kJ/g$

protein is $17 kJ/g$

$26 g$ of carbohydrate is $26 \mathrm{g}\times 17 kJ/\mathrm{g}=442 kJ$

 $2 g$of protein is $2 \mathrm{g}\times 17 kJ/\mathrm{g}=34 kJ$

The Energy total is $442 kJ+34 kJ=476 kJ$

As a result, for one cup of orange juice total energy is $476 kJ.$

(Part b) Step3: Given information .

Given data are: no fat and no protein and $72 kcal$ of energy in apple.

To find the grams of carbohydrate in one apple  .

(Part b) Step4: Carbohydrate in one apple

Apple total energy is $72 kcal$

$Total energy = energy value of carbohydrate\times mass$

Proteins and fats are not present.

$72 k\mathrm{cal}=4 k\mathrm{cal}/\mathrm{g}\times \text{ mass }$

$\text{ mass }=\frac{72 k\mathrm{cal}}{4 k\mathrm{cal}/\mathrm{g}}=18 \mathrm{g}$

As a result, carbohydrates in one apple is $18 g.$

(Part c) Step5: Given information.

Given data are:$14 g$ fat and no carbohydrates and protein.

To find the kilocalories in one tablespoon of vegetable oil .

(Part c) Step6: One tablespoon of vegetable oil .

Fat energy value is $9 kcal/g$

$14 g$of fat value is $14 \mathrm{g}\times 9 k\mathrm{cal}/\mathrm{g}=126 k\mathrm{cal}$

As a result, one teaspoon of vegetable oil is $126 kcal.$

(Part d) Step7: Given information .

Given data are:$13 g$ carbohydrates and $5 g$ protein and $405 kcal$.

To find the grams of fat in one avocado  .

(Part d) Step8: Grams of fat in one avocado .

One avocado total energy is $405 kcal$

Carbohydrate value is $4 kcal/g$

Protein energy value is $4 kcal/g$

 $13 g$of carbohydrate energy value is $13 \mathrm{g}\times 4 k\mathrm{cal}/\mathrm{g}=52 k\mathrm{cal}$

 $5 g$ of protein energy value is $5 \mathrm{g}\times 4 k\mathrm{cal}/\mathrm{g}=20 k\mathrm{ca}l$

The total of carbohydrates and protein energy is $=(52+20) k\mathrm{cal}=72 kcal.$

Fat energy is $405 k\mathrm{cal}-72 k\mathrm{cal}=333 k\mathrm{cal}$

Fat energy value is $9 kcal/g$

(Part d) Step: 9 Substituting:

Solving,

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

$333 k\mathrm{cal}=9 k\mathrm{cal}/\mathrm{g}\times \text{ mass }$

$\text{ mass }=\frac{333 k\mathrm{cal}}{9 k\mathrm{cal}/\mathrm{g}}=37 \mathrm{g}$

As a result, one avocado fat is $37 g.$