Molarity and dilution
Before you read
Test yourself first: 5 questions
Question 1 of 5
Diffusion moves particles from an area of high concentration to an area of ____ concentration.
Answer: B. Diffusion moves particles down their concentration gradient — from high to low.
Question 2 of 5
In a solution, concentration describes how much ____ is dissolved.
Answer: B. Concentration is the amount of solute dissolved in a given amount of solvent.
Question 3 of 5
The movement of molecules from an area of high concentration to low concentration, without energy, is:
Answer: B. Diffusion is passive movement down a concentration gradient. Active transport moves against the gradient and needs ATP.
Question 4 of 5
Adding more solvent to a solution makes it more:
Answer: A. Concentration is solute per unit of solvent. More solvent, same solute → dilute. More solute, same solvent → concentrated.
Question 5 of 5
A solution with a pH of 3 is:
Answer: A. The scale runs 0–14: below 7 acidic, exactly 7 neutral, above 7 basic. Each whole unit is a tenfold change in hydrogen-ion concentration.
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