Q3 Summary

​Quarter 3 Summary

​Write notes as you go through this review.

This is NOT a suggestion/ request.

This is how this will work

• Each topic we covered will be reviewed one at a time.

• practice questions will follow each topic.

• Write notes/examples

3. The unit for molar mass is g/mol (#g = 1 mol)

4. We use this to convert between mass and moles

1. The mass of an element/ compound

2. Use the decimal number from the periodic table

Molar Mass is....

Topic 1: Molar Mass

The molar mass of Cl (chlorine) would be

35.45 g/mol

35.45 g= 1 mol Cl

Calculating element

Topic 1: Molar Mass

Calculating Compound

KNO₃

You need to find molar mass for each.

If there is more than one of that element, multply by that number

For extra examples of calculating molar mass click this link

LINK

Multiple Choice

What is the molar mass of Cl

• 12.01 g/mol

• 30.0 g/mol

• 35.45 g/mol

Multiple Choice

What is the molar mass of Mg₃(PO₄)₂

• 200.85 g/mol

• 262.855 g/mol

• 180 g/mol

1. Mass to moles, moles to mass, you use..... MOLAR MASS

2. The unit for molar mass is g/mol ( connecting moles to mass)

3. #g is what you calculate

4. # moles is always 1

Topic 2: Converting Mass to moles

• Underline what you know/circle what you are looking for

• Start with what you know

• You want to cancel the unit you start with ..so... it goes to the....... BOTTOM

• The unit you circled is what goes on top

• Fill in your numbers

​Where to start

How many moles are in 20 g of Ca.

​

​Example

• You know- 20 g Ca

• You want to find- moles of Ca

• mass to moles, moles to mass, you use molar mass

• We start with what we know (20g) and we want to cancel that unit out.

• grams goes on the bottom

• what we are looking for goes on top (mols)

• Fill in NUMBERS

​

For extra examples of converting mass to moles CLICK this link

LINK

Multiple Choice

How many moles are equal to 45.6 g of NaCl

• 1.00 mole of NaCl

• 0.780 moles of NaCl

• 1.56 moles of NaCl

Multiple Choice

How many grams are equal to 5.6 moles of MgCl₂

• 535.4 g MgCl₂

• 333.6 g MgCl₂

• 203.3 g MgCl₂

1. Use Avogadro's number to convert (6.02 X 10²³)

2. 1 mol = 6.02 X 10²³ molecules

   atoms

   particles

   formula units

Topic 3: Converting moles to particles (molecules, atoms, or formula units)

• Underline what you know/circle what you are looking for

• Start with what you know

• You want to cancel the unit you start with ..so... it goes to the....... BOTTOM

• The unit you circled is what goes on top

• Fill in your numbers

​Where to start

How many atoms are in 5 moles of Zn

​

​Example

• You know- 5 mol Zn

• You want to find- atoms of Zn

• atoms tells you to use avogadro's number

• We start with what we know (5 mol) and we want to cancel that unit out.

• mole goes on the bottom

• what we are looking for goes on top (atoms)

• Fill in NUMBERS

​

For extra examples of converting moles to particles CLICK this link

LINK

Multiple Choice

How many atoms are in 4.5 moles of NaCl

• 2.71x10²⁴ atoms Zn

• 7.5x10^-24 atotms Zn

• 3.75x10²⁴ atoms Zn

Multiple Choice

How many moles are equal to 5.6x10²⁰ particles of HCl

• 7.5x10^-24 mols HCl

• 0.0009 moles of HCl

• 3.75 moles HCl

Topic 4: Types of Reactions

5 types of reactions

For extra examples for ID types of reaction CLICK this link

LINK

Multiple Choice

What type of reaction is this

2KNO₃--> 2KNO₂+ O₂

• Synthesis

• Decomposition

• Single displacement

Multiple Choice

What type of reaction is this

2H₂+O₂--> 2H₂O

• Synthesis

• Decomposition

• Double displacement

Multiple Choice

To ID a single displacement reactions you should look for this on both sides of the arrow

• element & element

• element & compound

• Compound & Compound

Multiple Select

When ID a combustion reaction you should look for

• CO₂

• H₂O

• C_xH_y

• O₂

Topic 5: Balancing Reactions

• Start a table- list what you are starting with on each side.

• Your goal is to get both sides of the table to match by changing the COEFFIENTS

• As you add coefficients, update your table

​Where to start

​Example

• ​Make table

• Start with how many is on each side ( count the subscripts [small numbers])

• Add coefficients to balance each side

For extra examples for balancing equations CLICK this link

LINK

Multiple Choice

What should the coefficients be to balance this equation

H₂+O₂--> H₂O

• 1,1,1

• 2,1,2

• 2,1,1

Multiple Choice

What shoud the coefficients be to balance this equation

C₃H₈ + O₂ → CO₂ + H₂O

• 1,5,3,4

• 2,10,6,8

• 2,5,6,8

Topic 6: Stoichiometry pt.1

The equation connects each compound to each other

​Tells us the relationship of elements using a balanced chemcial equation

You must have 4 moles of NH₃ & 3 moles of O₂ to produce 2 moles of N₂ & 6 moles of H₂O

​Example

How many moles of O₂ are equal to 11 moles of NH₃

1. Under line what you know/circle what you are looking for

2. start with what you know

3. cancel out the unit you start with

4. Put unit you want on top

​Mole A to Mole B

For extra examples Mole to mole

CLICK this link

LINK https://youtu.be/3zmeVamEsWI

Multiple Choice

How many moles of N₂ are equal to 5.7 moles of O₂

• 3.8 mol N₂

• 11.4 mol N₂

• 1.9 mol N₂

Multiple Choice

How many moles of NH₃ are equal to 12.6 moles of H₂O

• 3.8 mol N₂

• 18.9 mol NH₃

• 8.4 mol NH₃

Topic 6: Stoichiometry pt.2

The equation connects each compound to each other

​Tells us the relationship of elements using a balanced chemcial equation

You must have 4 moles of NH₃ & 3 moles of O₂ to produce 2 moles of N₂ & 6 moles of H₂O

​Example

1. Under line what you know/circle what you are looking for

2. start with what you know

3. cancel out the unit you start with

4. We have to do 2 steps to complete these

​Mole A to Mole B to Mass B

2 steps are required

For extra examples Mole A- Mole B- Mass B

CLICK this link

LINK

Multiple Choice

How many moles of NH₃ are equal to 12.6 grams of H₂O

• 1.05 mol NH₃

• 0.466 mol NH₃

• 8.0 mol NH₃

Multiple Choice

How many grams of NH₃ are equal to 6.4 moles of H₂O

• 20.8 g NH₃

• 45.6 g NH₃

• 72.7 g NH₃