Question

question 18 (5 points)
what happens when gas is compressed by pressure?
particles move closer together
none are true
particles move farther apart
both are true
question 19 (5 points)
which of the following is an example of a physical property?
reactivity with acid
flammability
ability
boiling point

Explanation:

• For Question 18: When gas is compressed by pressure, according to the kinetic - molecular theory of gases, the volume available for gas particles decreases. So, the particles move closer together.
• For Question 19: A physical property is a characteristic of a substance that can be observed or measured without changing the substance's chemical composition. Reactivity with acid and flammability are chemical properties as they involve chemical changes. "Ability" is too vague. Boiling point is a physical property as it can be measured without altering the substance's chemical nature.

Answer:

Question 18: A. particles move closer together
Question 19: D. boiling point