Chemistry - 2nd Quarter Review

Front

What is the most abundant element in the universe?

Back

Hydrogen

Front

What are isotopes?

Back

Isotopes are variants of a particular chemical element that have the same number of protons but different numbers of neutrons. Examples include Carbon-12, Carbon-13, and Carbon-14.

Front

How do you balance the equation P4 + O2 → P4O6?

Back

The balanced equation is P4 + 3O2 → P4O6.

Front

What is 0.00432 in scientific notation?

Back

4.32 x 10^-3

Front

How many O2 molecules are needed to balance the equation 2C2H6 + ___O2 → 4CO2 + 6H2O?

Back

7

Front

Define atomic number.

Back

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

Front

What is a chemical reaction?

Back

A chemical reaction is a process that leads to the transformation of one set of chemical substances to another.

Front

What is the law of conservation of mass?

Back

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

Front

What is a mole in chemistry?

Back

A mole is a unit of measurement used to express amounts of a chemical substance, defined as exactly 6.022 x 10^23 particles.

Front

What is the difference between an element and a compound?

Back

An element is a pure substance that cannot be broken down into simpler substances, while a compound is a substance formed when two or more elements are chemically bonded together.