Chemistry Exam Review II

Front

What is the atomic number of an element?

Back

The atomic number is the number of protons in the nucleus of an atom, which determines the element's identity.

Front

How do you determine the number of neutrons in an atom?

Back

The number of neutrons can be found by subtracting the atomic number from the atomic mass (rounded to the nearest whole number).

Front

What is a chemical change?

Back

A chemical change occurs when substances combine or break apart to form new substances, such as rusting iron.

Front

What is a physical change?

Back

A physical change is a change that affects one or more physical properties of a substance without altering its chemical composition.

Front

How do you balance a chemical equation?

Back

To balance a chemical equation, ensure that the number of atoms of each element is the same on both sides of the equation.

Front

What is the significance of the coefficients in a balanced equation?

Back

Coefficients indicate the number of molecules or moles of a substance involved in a reaction.

Front

What is the formula for calculating the number of electrons in a neutral atom?

Back

In a neutral atom, the number of electrons equals the number of protons.

Front

What is an isotope?

Back

An isotope is a variant of a chemical element that has the same number of protons but a different number of neutrons.

Front

What does it mean for a reaction to be exothermic?

Back

An exothermic reaction releases energy, usually in the form of heat, to its surroundings.

Front

What does it mean for a reaction to be endothermic?

Back

An endothermic reaction absorbs energy from its surroundings, resulting in a decrease in temperature.