Physical Science Midterm

Front

What happens to the speed of molecules when a substance changes from a gas to a liquid?

Back

The speed of the molecules decreases, because they have lower kinetic energy in the liquid state.

Front

What type of reaction is represented by the equation: 2 N2 + 3 H2 -> 2 NH3?

Back

This is a synthesis reaction.

Front

How can a student transform gaseous carbon dioxide into solid carbon dioxide?

Back

The student must remove energy from the sample.

Front

What is a key characteristic of compounds with covalent bonds?

Back

They share electrons to form bonds.

Front

What determines the identity of an atom?

Back

The number of protons.

Front

What is kinetic energy?

Back

Kinetic energy is the energy of an object due to its motion.

Front

What is the difference between an element and a compound?

Back

An element is a pure substance made of only one type of atom, while a compound is made of two or more different types of atoms chemically bonded together.

Front

What is the law of conservation of mass?

Back

The law states that mass is neither created nor destroyed in a chemical reaction.

Front

What is a chemical reaction?

Back

A process that involves the rearrangement of the molecular or ionic structure of a substance.

Front

What is the pH scale used for?

Back

The pH scale measures the acidity or basicity of a solution.