General Science: Physics and Chemistry Concepts Flashcards

What is the term for the minimum energy required to start a chemical reaction?

Answer: Activation energy

Activation energy is the minimum energy needed to initiate a chemical reaction by breaking existing bonds.

Which phenomenon explains why a straw appears bent when placed in a glass of water?

Answer: Refraction

Refraction occurs when light changes speed as it passes from one medium (air) to another (water), bending the apparent position of objects.

What is the correct representation of water's chemical formula?

Answer: H₂O

Water consists of two hydrogen atoms covalently bonded to one oxygen atom, giving the formula H₂O.

According to Charles's Law, what happens to the volume of a gas when temperature increases at constant pressure?

Answer: Volume increases

Charles's Law states that volume and temperature are directly proportional at constant pressure, so higher temperature means greater volume.

Which of the following is NOT a form of potential energy?

Answer: Kinetic energy of a moving car

Kinetic energy is the energy of motion, not stored (potential) energy; the other choices are all forms of stored energy.

What is the term for a substance that speeds up a chemical reaction without being consumed?

Answer: Catalyst

A catalyst lowers the activation energy of a reaction and is not consumed in the process, allowing it to be reused.

Which property of a wave determines its pitch when heard as sound?

Answer: Frequency

The pitch of a sound is determined by its frequency; higher frequency waves produce higher-pitched sounds.