Question

Which ideas are key to balancing chemical equations and knowing what a reaction will make?

(Select the two correct answers.)

(2 points)
Responses

The reaction speed determines the final products.
The reaction speed determines the final products.

The valence electrons guide how atoms combine.
The valence electrons guide how atoms combine.

The types of atoms can change during reactions.
The types of atoms can change during reactions.

The total mass of products is always less.
The total mass of products is always less.

The number of molecules must be conserved.
The number of molecules must be conserved.

The number of each atom type is conserved.

Answer 1

- The valence electrons guide how atoms combine.
- The number of each atom type is conserved.

Explanation (brief): Valence electrons determine how atoms bond and what products form; the conservation of atoms (and mass) is why you must balance the number of each element on both sides of an equation.