Chemistry midterm review

Front

What explains why noble gases are unreactive?

Back

Their outer electron shells are full.

Front

How many neutrons does Element X have if it has 11 protons and a mass of 23 amu?

Back

12 neutrons.

Front

What type of change occurs when water dissolves?

Back

Physical change.

Front

What is the balanced equation for burning magnesium in oxygen?

Back

2 Mg + O₂ → 2 MgO.

Front

What is the formula for Iron(II) oxide?

Back

FeO.

Front

What is the definition of an isotope?

Back

Atoms of the same element with different numbers of neutrons.

Front

What is the principle behind the law of conservation of mass?

Back

Mass is neither created nor destroyed in a chemical reaction.

Front

What is a chemical change?

Back

A change that results in the formation of new chemical substances.

Front

What is the difference between a homogeneous and heterogeneous mixture?

Back

Homogeneous mixtures have a uniform composition, while heterogeneous mixtures do not.

Front

What is the definition of a mole in chemistry?

Back

A mole is 6.022 x 10²³ particles of a substance.