Question

1. what are electrolytes, and what purposes do they serve in the human body? (p. 1)
2. in the video (on page 3), explain why the sucrose solution did not complete the circuit, but the salt solution did.

Explanation:

Question 8

Electrolytes are substances that ionize in solution (like salts, acids, bases) and conduct electricity. In the human body, they maintain fluid balance, regulate nerve and muscle function (e.g., Na⁺, K⁺ for action potentials), balance pH, and support osmotic pressure. For example, sodium helps with fluid volume, potassium with muscle contractions.

Sucrose (table sugar) is a covalent compound (disaccharide, made of glucose + fructose). In solution, it dissolves as intact molecules, not ions—so no charge carriers to conduct electricity, hence the circuit isn’t completed. Salt (e.g., NaCl) is an ionic compound. In water, it dissociates into Na⁺ and Cl⁻ ions. These mobile ions carry electric charge, allowing current to flow and complete the circuit.

Answer:

Electrolytes are substances (like salts, acids, bases) that dissociate into ions in solution (or melt) and conduct electricity. In the human body, they: 1) Regulate fluid balance (e.g., Na⁺, Cl⁻ for extracellular fluid, K⁺ for intracellular fluid). 2) Facilitate nerve impulses (ion gradients for action potentials) and muscle contractions (e.g., Ca²⁺ in muscle fibers). 3) Maintain acid - base balance (buffering, e.g., HCO₃⁻). 4) Support osmotic pressure (driving water movement between compartments).

Question 9