7.1 Counting Atoms

Front

What is a coefficient in a chemical equation?

Back

A coefficient is a number placed in front of a chemical formula in an equation to indicate how many molecules or moles of that substance are involved in the reaction.

Front

How do you balance a chemical equation?

Back

To balance a chemical equation, adjust the coefficients of the reactants and products so that the number of atoms of each element is the same on both sides of the equation.

Front

What is the Law of Conservation of Mass?

Back

The Law of Conservation of Mass states that during a chemical reaction, mass is neither created nor destroyed.

Front

How many atoms of hydrogen are in one molecule of water (H2O)?

Back

There are 2 atoms of hydrogen in one molecule of water.

Front

How many total atoms are in the compound H3PO4?

Back

There are 8 total atoms in H3PO4 (3 H, 1 P, and 4 O).

Front

What is the total number of oxygen atoms in Fe(NO3)3?

Back

There are 9 oxygen atoms in Fe(NO3)3 (3 NO3 groups, each containing 3 O).

Front

How many hydrogen atoms are in 4H2O?

Back

There are 8 hydrogen atoms in 4H2O (4 x 2 H).

Front

What is the significance of balancing chemical equations?

Back

Balancing chemical equations ensures that the same number of each type of atom is present on both sides of the equation, reflecting the conservation of mass.

Front

What does it mean if a chemical equation is unbalanced?

Back

An unbalanced chemical equation does not accurately represent the conservation of mass, meaning the number of atoms of each element is not the same on both sides.

Front

What is a reactant in a chemical reaction?

Back

A reactant is a substance that undergoes change during a chemical reaction.