Question

triglycerides form when three fatty acid molecules combine with one molecule of glycerol, which contains carbon, oxygen, and hydrogen atoms. fatty acids have carbon and hydrogen atoms arranged in long chains. the number of carbon atoms in a fatty acid can range from four to 36! the models show the chemical structures of stearic acid (a fatty acid) and stearin (a triglyceride). how many molecules of stearic acid are needed to make one molecule of stearin?

Explanation:

Step1: Analyze the structure of stearin

Looking at the stearin (triglyceride) structure, we can see the fatty acid chains attached to the glycerol backbone.

Step2: Recall the formation of triglycerides

Triglycerides (like stearin) form when three fatty acid molecules combine with one glycerol molecule. From the structure of stearin, we can count the number of fatty acid (stearic acid - like) chains. Each of these chains comes from a stearic acid molecule. By observing the stearin structure, we see three fatty acid - derived chains.

Step3: Determine the number of stearic acid molecules

Since each fatty acid chain in stearin is from a stearic acid molecule, and there are three such chains (as per the structure and the definition of triglycerides: 3 fatty acids + 1 glycerol), the number of stearic acid molecules needed is 3.

Answer:

3