Parts of Equations

CHEMICAL vs. MATH EQUATIONS

Chemical equations are similar to math equations.

CHEMICAL vs. MATH EQUATIONS

Items are separated with a + symbol. The right side of the equation is the result of what happens on the left side of the equation.

Match

Match the following

• A

• B

• C

• D

• E

reactant(s)

yields

product(s)

subscript

coefficient

• reactant(s)

• yields

• product(s)

• subscript

• coefficient

CHEMICAL vs. MATH EQUATIONS

Math equations have an equal sign.
Chemical equations have an arrow.

Cake

​Finished product

Flour
Sugar
Egg
Oil

​Ingredients (reactants)

Imagine baking a cake.
You start with certain ingredients and end with a delicious result.

​------->

​Reactants are written on the left side of an arrow. They are the ingredients needed for the reaction to occur.

Products are written on the right side of an arrow. They are what the reaction makes.

​Yield means "becomes."

In the cake example, the ingredients yield the cake.

Multiple Choice

Is the compound in the pink box a Reactant or a Product? (aq means aqueous or water)

• Reactant

• Product

Multiple Choice

A reactant is always on the right

• False

• True

Multiple Choice

A product is on the left and right

• False

• True

Multiple Choice

 Which ones is/are the reactant(s)?

2HO +  Na  ------>  H₂O + 2Na

• H₂O

• 2HO , Na

• H₂O, 2Na

Multiple Choice

There are four hydrogen atoms present at the beginning of the reaction, but only two at the end of the reaction. $$CH_4+2O_2→CO_2+2H_2O$$  

• True

• False

Multiple Choice

What is the right part of a chemical equation called?
H_{2 +} O → H₂O

• Reactant(s)

• Product(s) 

• Yields 
• Chemical Equation 

​Coefficients tell us how many molecules (sets of atoms there are in a formula).

2 HCl means there are 2 H and 2 Cl
atoms before the reaction happens

2 Na means there are 2 Na atoms before the reaction occurs

Subscripts tell us how many atoms there are bonded in a molecule

H₂ tells us there are 2 H atoms after the reaction occurs

4Fe + 3O₂ ➡️ 2Fe₂O₃

The reactants are four iron atoms & three molecules of oxygen gas (O₂). Each molecule of oxygen gas is made up of two oxygen atoms. Since the reactants include three oxygen molecules, there are a total of six oxygen atoms in the reactants.


The product of this reaction is iron oxide. Two molecules of iron oxide form. Each molecule has the formula Fe₂O₃. The formula Fe₂O₃ shows that a molecule of iron oxide contains two iron atoms and three oxygen atoms. Since there are two molecules of iron oxide, the product contains a total of 4 iron atoms and 6 oxygen atoms.

Multiple Choice

This appears on the left side of a chemical formula, and represents how many molecules there are. 

• An Atom
• The Subscript
• A Molecule
• The Coefficient

Multiple Choice

How many hydrogen atoms are in 4H₂O?

• 6

• 8

• 2

• 4

Multiple Choice

How many oxygen atoms are in 4H₂O?

• 6

• 8

• 2

• 4

Multiple Choice

A ______ is a number written in front of a chemical formula.

• Coefficient

• Subscript

• Exponent

• Coordinator