# PPT on 1.2 The mole concept

PPT on 1.2 The mole concept has following keywords:

Mole, Avogadro’s Number,Molar Mass,Relative Atomic Mass,Relative Molecular Mass,Empirical Formula,Molecular Formula

PPT on 1.2 The mole concept aligns with the IB Diploma Chemistry Guide. It covers the past paper questions on this subtopic.

Objectives: This Page enables the students to apply their learning to calculate the molar masses of chemical species like atoms, molecules and ions. They can calculate the amount of reactants and products in moles and the mass in grams. They can determine the empirical formula and molecular formula from the percentage abundance of the constituent elements. The students can calculate moles, molar mass and mass of a substance.

Guidance: The Mole is a quantity while mol is it’s unit. Often students remain confused about the difference.

Now can you answer the following questions:

What is 1Mole?

Determining Empirical formula

Step 1: Write the element symbols along with % given. Consider % as mass in gram.

Step 2: Divide the given mass of each element by relative atomic mass of that element.

( mole=mass/molar mass) so you get moles of each element here.

Step 3: Divide the moles of each element by the smallest moles obtained in step 2.

Step 4: Use the obtained values as number of atoms per element in empirical formula.

Note : if you did not get the whole number values, do not simply round off the values but multiply by suitable integers to make the value whole number. Example if you get 2.5, do not round simply to 3 but multiply 2.5 by 2 to get 5 which is a whole number.

A compound has 44.09 % iron and rest chlorine. Determine its emp formula.  If the molar mass of the compound is 127 g/mol, determine its Molecular formula as well.

You can go to the next subtopic 1.3 Reacting masses and volumes PPT here.

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