Question

Glucose is a type of sugar molecule made of carbon, hydrogen, and oxygen. In the body, glucose combines with oxygen to form palmitic acid, water, and carbon dioxide. Palmitic acid is a fatty acid found in both plants and animals.

The image below models this reaction. In the actual reaction, more than one of each type of molecule may be used or produced.

glucose (C6H12O6) and oxygen (O2) react to become palmitic acid (C16H32O2), carbon dioxide (CO2), and water (H2O)

What must be true of the actual reaction but is not shown in the model?
A.
Every carbon atom from the glucose molecule must end up in a molecule of palmitic acid.
B.
Every glucose molecule joins with another glucose molecule to form a molecule of palmitic acid.
C.
The number of oxygen atoms in the glucose and oxygen must equal the number of oxygen atoms in the palmitic acid, water, and carbon dioxide.
D.
The number of glucose molecules at the beginning of the reaction must equal the number of palmitic acid molecules at the end of the reaction.

Answer 1

C.

Chemical reactions must conserve atoms (mass). The total number of oxygen atoms in the reactants (glucose + O2) must equal the total number of oxygen atoms in the products (palmitic acid + CO2 + H2O). Options A, B, and D are not necessarily true in the actual balanced reaction.