Moles

Mole and equations
Made by: Hala

what is a chemical equation and how to balance it?

chemical equation is a way to show a chemical reaction using symbols and formulas. When balancing it you must make sure that the numbers of each type of atom on both sides of the equation are the same.

Balancing equations

For example the following equation is not balanced:
CH4 + O2 --> CO2 + H2O
C=1 C=1
H= 4 H=2
O=2 O=3
To make it balanced you should add a 2 infront of the O2 and and 2 in front of the H2O ( remember you cannot change the subscript)
CH4 + 2O2--> CO2 + 2H2O

Multiple Choice

Balance this equation

AL + O2 ---> AL2O3

• 2Al + 2O2 ---> Al2O3
• 4Al + 3O2 ---> 2Al2O3
• 3Al + 3O2 ---> Al2O3
• 4Al + 2O2 ---> 2Al2O3

Multiple Choice

Balance this equation

Na + CL2 ---> NaCl2

• 2Na + Cl2 ---> 2NaCl
• The equation is already balanced
• Na + 2Cl2 ---> NaCl
• Na + Cl2 ---> NaCl2

What is a mole?

A mole is a unit used to measure the quantity of many objects. One mole contains about 6.022 x 10^23 particles, which is known as Avogadro's number.

What is molar mass?

Molar mass is the mass of one mole of a substance (g/mole). You may find the molar mass of one mole by finding the atomic mass of an element. However if you're looking for the molar mass of a compound you have to add the molar mass of both of the elements.

Multiple Choice

calculate the molar mass of Na2Cl

• 74.44 g/mol
• 58.93 g/mol
• 90.11 g/mol
• 36.22 g/mol

Multiple Choice

What is Avogadro's number?

• 5.678 x 10^23
• 6.022 x 10^22

• 10^23
• 6.022 x 10^23

When the amount of moles are not given you must divide depending on what you have whether it will be the amount of liters and grams or particles.
For example: if you have the amount of liters which will always be 22.4 and the grams you must divide the liters by grams inorder to find the moles.

​when it's not given

​when the amount of moles are given you must multiply depending on what you have to find.
For example: if you are trying to find the amount of particles you must multiply the amount of moles by 6.02x10^23 inorder to find the particles.

​when it's given

How do you calculate the amount of moles:

What are the equations for calculating ?

Multiple Choice

How many moles of oxygen are present at STP level?

• 1 mole
• 3 moles
• 0.5 moles
• 2 moles

Multiple Choice

How many molecules are there in 1 moles of H2O

• 6.022 x 10^23
• 5.022 x 10^23
• 1.205 x 10^24
• 3.011 x 10^23