PAX PAX Chemistry and Physical Science 2

Question 1

What happens during an exothermic reaction?

Accepted Answer

Energy is released to the surroundings

Answer

Exothermic reactions release energy (usually heat) to the surroundings, causing the temperature to rise.

Question 2

What is the formula for calculating density?

Accepted Answer

Density = Mass / Volume

Answer

Density is defined as mass divided by volume (D = m/V) and is typically expressed in g/cm³ or g/mL.

Question 3

An acid and a base react to form water and a salt. This type of reaction is called:

Accepted Answer

Neutralization

Answer

A neutralization reaction occurs when an acid and a base react to produce water and a salt.

Question 4

What is Newton's First Law of Motion?

Accepted Answer

An object at rest stays at rest unless acted on by an external force

Answer

Newton's First Law states that an object remains at rest or in uniform motion unless acted upon by a net external force (law of inertia).

Question 5

Which of the following is a chemical change?

Accepted Answer

Wood burning

Answer

Burning wood is a chemical change because it produces new substances (ash, CO₂, water vapor) that cannot be reversed.

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