Chemistry Centre
In this section we will learn how to find the molar mass
From the mole concept we learned (M) = Molar mass (g/mol)
The molar mass can easily be calculated by adding the atomic mass' of each given element.
Example: Determine the molar mass of iron(II) sulphite
Step 1. Write out each element within the compound including coefficients
MFe2(SO3)3 = 2MFe + 3MS + 9Mo
Step2. Multiply the coefficient with its specific element. Add each atomic mass of the given elements together. (include: g/mol)
MFe2(SO3)3 = 2(55.85g/mol) + 3(32.06g/mol) + 9(16.00g/mol)
Step 3. Calculate the final Molar Mass
MFe(SO3)3= 351.88g/mol
Step 4. End with a concluding sentence
Therefore the molar mass of iron (II) sulphite is 351.88g/mol
Involving molar mass
Lets take a look
Lets take a look
Lets take a look
When looking at a word equation, the key words that should be running through your head are: (mol) (amount) (mass) (molar mass) and (g). These indicate calculations involving Molar mass.
Depending on what your givens and unknowns are, this animated mole triange will help set up our formulas. This will indicate wheather we divide or multiple our givens.
In this section we will learn how to find moles
Once the mass number is found/given you are able to calculate the mole
Example: A typical can of cola contains 40.0g of sucrose (C12H22O11). Calculate the amount of sucrose in one can.
Step 1. Write out formula for mols and insert givens (find molar mass ahead of time)
n= m/MC12H22O11
n = 40.0g/ 342.35g/mol ------ remembering that the (g) cross' out
Step 2. Calculate the number of moles
n = 0.117mol
Step 3. End with a concluding sentence
Therefore, the amount of sucrose has 0.117mol of in a typical 40.0g can.
In this section we will learn how to find mass
Once the number of moles are found/given you are able to calculate the mass of the substance.
Example: A liter of human blood typically contains 4.0 X 10^-3mol of glucose C6H12O6. Calculate the mass of this amount.
Step 1. Write out formula for mass and insert givens (find molar mass ahead of time)
m = n(MC6H12O6)
m = 4.0x10^-3mol(180.18g/mol) ----- the mols cancel eachother out
Step 2. Calculate the mass of substance
m = 0.72g
Step 3. End with a concluding sentence
Therefore, there is 0.72g in a liter of human blood
Overview
xM
n--------->m
n<---------m
/M
mg -----> x10^-3
kg -----> x10^3
Definition: An element or compund is the mass of that substance when 1 mole of it is present.