Balancing Chemical Equations
Vocabulary
Key Concepts
Balanced and Unbalanced Equations
Type of reaction?
100
What is the Golden Rule, Thing you cannot change when balancing a chemical equation?
You cannot change a subscript
100
What are reactants?
The substance(s) presented before a chemical equation.
100
Atoms can't ever be __ or __ in a chemical reaction. The same number of atoms must always be __ each side of the equation.
created, destroyed, on
100
Why do we have to balance chemical equations?
Because atoms cannot be created or destroyed
100
What is the product in the following reaction? Na + Cl → NaCl
NaCl
200
Place the steps in order
1. Add all of the Element's atoms
2. Arrange the Elements vertically
3. Multiply everything by the Coefficient
4. Multiply everything within the Brackets.
2, 1, 4, 3
200
What are products?
The substance(s) produced after a chemical equation.
200
Is this reaction balanced or unbalanced? How do you know? H₂ + O₂ → H₂O
Unbalanced missing 1 Oxygen
200
Is the following equation balanced or unbalanced? Ca+ S --> CaS
Balanced, Their are equal amounts of atoms on either side.
200
What does the arrow (→) in a word equation mean?
Yields or Produces
300
What does a coefficient tell you in a chemical equation?
How many molecules of a substance are present
300
What is the difference between endothermic and exothermic?
Exo: releases energy and gets warmer
Endo: absorbs energy and gets colder
300
What is the term used for the elements and compounds after a chemical reaction takes place?
product(s)
300
What is the product in a chemical reaction?
What is created
300
In a chemical reaction, what does unbalanced mean?
Their are not equal amounts of atoms are either side of the equation
400
How many atoms are in 3O₂?
6
400
What is matter?
Anything that has mass and takes up space.
400
How do you know when a chemical equation is balanced?
When the element(s) and compound(s) on both side are the same.
400
How many total atoms are in the following equation?
Al2O3+ 6Cl2→ AlCl3+ 3O2
27
400
A chemical substance that is present at the start of a chemical reaction.
Reactant
500
How many Carbon Atoms are in 4NaCl?
0
500
What does balanced mean?
A balanced chemical equation correctly shows that no mass was created or destroyed during the reaction.
500
Is this chemical equation balanced or balanced? How do you know? C + O₂ → CO₂
Balanced, There are equal amounts of atoms on both sides of the equation
500
How many total atoms are in
3Zn(OH)2+ H3PO4→ Zn3(PO4)2+ H2O
39
500
What law requires that an equal amount of atoms of each element need to be present on either side of an equation?
Law of conservation of Mass
600
How many atoms of Sr, P, and O are in
Sr6, P4, O16
600
How many total atoms are in
28
600
Consider the unbalanced chemical reaction: H2+O2→H2OH2+O2→H2O. How many hydrogen molecules are needed to balance the equation?
4
600
What is the principle that states the number of each type of atom must be the same on both sides of a chemical equation?
Law of conservation of matter
600
Which of the following is NOT a sign of a chemical change?
Release light and heat
change in size
change of color
Change in size