Writing Chemical Equations

Review Questions

Multiple Choice

The reactants are on the left side of the chemical equation.

• True
• False

Multiple Choice

Two clear colorless solutions were combined.
The student observed that the temperature changed from 25 •C to 23 •C when the solutions were combined and that a white substance rapidly formed and settled to the bottom of the container. What most likely happened to produce these results?

• One of the original compounds came out of solution
• The solutions reacted chemically
• Some of the water froze into ice crystals
• Rapid evaporation of water occurred, leaving a solid

Multiple Choice

In a ___________change, a substance changes into a different substance.

• Physical

• Chemical

Multiple Choice

How many Sodium (Na) are in 6NaCl?

• 1
• 12
• 6

Multiple Choice

How many Hydrogen are in 4H₂O?

• 6
• 8
• 2
• 4

Writing Chemical Equations

​We Will
1 Define
2. Symbolism
3. Alternate Word and Chemical EQ forms
I Will
Practice and Apply what I have learned

Definitions

Word equation:

Describes a chemical reaction using the names of the reactants and products.

Chemical equation:

Describes a chemical reaction using the chemical formulas of the reactants and products.

Word versus Chemical Equations

Write the word equation for the reaction of methane and oxygen gas to form carbon dioxide and water vapor.

Multiple Choice

True/False: There are 2 reactants in the chemical equation below.
$$H_2\ +\ Cl_{2\ }\rightarrow\ HCl\$$  

• True

• False

Multiple Choice

Translate the word equation below:

Nitrogen reacts with Hydrogen to form Ammonia (NH₃).

• $$N\ \ \rightarrow\ H\ +\ NH_3$$
  

• $$N_2\ +\ H_2\ \rightarrow\ NH_3$$

• $$N\ +\ H\ \rightarrow\ NH_3$$

• $$N_2\ \rightarrow\ H_2\ +\ NH_3$$

Chemical Symbolism in States of Matter

​Symbol	​Meaning
​(s)	Solid​
​(l)	Liquid​
(g)​	Gas​
(aq)​	​Aqueous

Multiple Choice

What does the symbol "(s)" mean in the chemical equation?

CaO(s) + H₂O(l) --> Ca(OH)₂(s)

• CaO is a solid

• CaO is a liquid

• CaO is a gas

• gas is produced

Symbols Used When Writing Equations

Write the word equation for the reaction of methane and oxygen gas to form carbon dioxide and water vapor.

Let’s look at the problem again.

​Symbol	​Meaning
​	​Yields
​	​Reversible
​	​Precipitate
​	​Gas

Symbols Used When Writing Equations

Multiple Choice

A reversible reaction is signified by which symbol?

Symbols Used When Writing Equations

Draw

Draw a symbol that indicates a change in heat in the chemical equation below.

CaCo_{3 (s)} ---- CaO_(s) + CO_{2 (g)}

Let's try One Together

When solid copper (II) carbonate is heated, it produces solid copper (II) oxide and carbon dioxide gas. Write the chemical reaction equation.

Let's try One Together