Skip to main content
Ch.5 - Thermochemistry
Chapter 5, Problem 90b

(b) A particular chip snack food is composed of 12% protein, 14% fat, and the rest carbohydrate. What percentage of the calorie content of this food is fat?

Verified step by step guidance
1
Step 1: Understand the problem. We need to find the percentage of the calorie content that comes from fat in the snack food.
Step 2: Recall the caloric values for macronutrients. Protein and carbohydrates each provide 4 calories per gram, while fat provides 9 calories per gram.
Step 3: Assume a certain total mass of the snack food for simplicity, such as 100 grams. This makes it easy to calculate the mass of each macronutrient: 12 grams of protein, 14 grams of fat, and 74 grams of carbohydrates.
Step 4: Calculate the total calories from each macronutrient. Multiply the mass of each macronutrient by its respective caloric value: protein (12g x 4 cal/g), fat (14g x 9 cal/g), and carbohydrates (74g x 4 cal/g).
Step 5: Determine the percentage of calories from fat. Divide the calories from fat by the total calories from all macronutrients, then multiply by 100 to get the percentage.

Verified Solution

Video duration:
5m
This video solution was recommended by our tutors as helpful for the problem above.
Was this helpful?

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Caloric Content of Macronutrients

Different macronutrients provide varying amounts of calories per gram: proteins and carbohydrates each provide 4 calories per gram, while fats provide 9 calories per gram. Understanding these values is essential for calculating the contribution of each macronutrient to the total caloric content of a food item.
Recommended video:
Guided course
06:35
Effective Nuclear Charge Calculation with Slater's Rules

Percentage Composition

The percentage composition of a food item indicates the proportion of each macronutrient relative to the total mass. In this case, knowing that the snack is 12% protein, 14% fat, and the remainder carbohydrates allows us to determine the total percentage of calories derived from fat in relation to the overall caloric content.
Recommended video:
Guided course
04:19
Matter Composition

Total Caloric Calculation

To find the percentage of calorie content from fat, one must first calculate the total calories from each macronutrient based on their percentages and caloric values. Then, the calories from fat can be divided by the total calories to find the percentage contribution of fat to the overall caloric content of the snack.
Recommended video:
Guided course
01:23
Total Entropy Example