Counting atoms and balancing equations

Front

What is the purpose of balancing chemical equations?

Back

To ensure that the number of atoms of each element is the same on both sides of the equation, in accordance with the law of conservation of matter.

Tags

NGSS.MS-PS1-5

Front

What does a coefficient represent in a chemical equation?

Back

A coefficient is the large number placed in front of a chemical formula that indicates how many molecules or moles of that substance are involved in the reaction.

Front

How do you determine the number of atoms in a compound?

Back

By multiplying the coefficient by the subscript of each element in the compound.

Tags

NGSS.MS-PS1-1

Front

What is the law of conservation of mass?

Back

In a chemical reaction, matter is neither created nor destroyed; the total mass of reactants equals the total mass of products.

Tags

NGSS.MS-PS1-5

Front

Balance the equation: _H2 + _O2 -> _H2O

Back

2H2 + O2 -> 2H2O

Tags

NGSS.MS-PS1-5

Front

What is a reactant in a chemical equation?

Back

A substance that undergoes a chemical change in a reaction, found on the left side of the equation.

Tags

NGSS.MS-PS1-5

Front

What is a product in a chemical equation?

Back

A substance that is formed as a result of a chemical reaction, found on the right side of the equation.

Tags

NGSS.MS-PS1-5

Front

How many atoms of chlorine are in 3CaCl2?

Back

6 (because 3 x 2 = 6 chlorine atoms).

Tags

NGSS.MS-PS1-1

Front

What is the significance of subscripts in a chemical formula?

Back

Subscripts indicate the number of atoms of each element in a molecule.

Tags

NGSS.MS-PS1-1

Front

Balance the equation: _Fe + _O2 -> _Fe2O3

Back

4Fe + 3O2 -> 2Fe2O3

Tags

NGSS.MS-PS1-5