chemical equations

Interpreting
chemical
Equations

Chemical
Equations

• Scientists use chemical

Equations to represent atoms
and molecules and how they
change during a chemical or
physical change

State Symbols

• (s) = solid

• (l) = liquid

• (g) = gas

• (aq) = aqueous or dissolved in water

Multiple Choice

Is the state of matter that has no definite shape or volume.

• Gas

• Liquid

• Viscosity

• Solid

Multiple Choice

Is the state of matter that has a definite volume but takes the shape of its container

• Gas

• Liquid

• Solid

• Viscosity

Multiple Choice

Is the state of matter that has a definite shape and volume

• Gas

• Liquid

• Viscosity 

• Solid

Multiple Choice

Are the physical forms in which a substance can exist.

• Solid

• Liquid

• State of matter

• Gas

Chemical Equation

Chemical
Reaction
Description

• A chemical reaction takes place.

Solid iron is added to aqueous
hydrochloride acid and reacts to
form hydrogen gas and aqueous
iron chloride. For every mole of
iron and two moles of
hydrochloric acid that react,
87.9 kJ of heat is given off.

Balanced vs.
Unbalanced

• It is important to balance

chemical equations properly
because balanced equations are
useful for calculating amounts of
each compound or element that
are needed for a reaction or
should be produced during a
reaction.

Multiple Choice

What's unbalanced about this equation? 

Al + O₂ --> Al₂O₃

• Oxygen (O) only

• Aluminum (Al) only

• Both oxygen and aluminum

• Nothing; it is balanced.

Chemical reaction description

Tips for writing and balancing

Tips for writing and balancing

Tips for

writing and
balancing

Multiple Choice

What coefficient should be used to make the following equation balanced?
N₂+O₂--> _NO 

• 1

• 2

• 3

• 4

Multiple Choice

How many HCl molecules do you need to balance this equation? 
Mg +  __HCl --->  MgCl₂ + H₂

• 1

• 2

• 3

• 4

Multiple Choice

Which of the following equations are correctly balanced?

• 12CO₂ +H₂O --> C₆H₁₂O₆ + O₂

• CO₂ + 9H₂O --> C₆H₁₂O₆ + O₂

• CO₂ + H₂O --> 3C₆H₁₂O₆ + O₂

• 6CO₂ + 6H₂O --> C₆H₁₂O₆ + 6O₂

Multiple Choice

Balance this equation...
HgO --> 2Hg + O₂

• It is balanced 

• 2HgO --> Hg + O₂

• 2HgO --> 2Hg + O₂

• I don't know...Oh well!

Multiple Choice

Balance this equation...
H₂ + Cl₂ --> HCl

• It is balanced 

• 3H₂ + Cl_{2 -->} 6H₂Cl

• H₂ + Cl_{2 --> 2HCl}

• I don't know! Oh well.

Multiple Choice

Which of the following shows the correct way to balance the chemical equation?
Fe + O₂ -> Fe₂O₃

• 4Fe + 3O₂ -> 2Fe₂O₃

• 2 Fe + 3O₂ -> Fe₂O₆

• 4 Fe + O₆ -> 2Fe₂O₃

• None of the options are correctly balanced.

Multiple Choice

What is a coefficient?

• The small number on the right of the chemical symbol.

• The large number in front of a chemical formula.

• The number in between the chemical symbols.

• The number behind a chemical formula.

Multiple Choice

What is the part of the chemical equation in green called? 
Fe + S --> FeS

• products

• reactants

• yield

• chemical formula

Multiple Choice

What is the little number after an element in a chemical equation called.
Example: H₂

• Coefficient 

• Subscript

• Atom

• Equation

Multiple Choice

Is this balanced?
Al + O₂ → 2Al₂O₃

• Yes

• No