### How can we Calculate Concentration?

This post will go through some formulae applied to find and manipulate concentrations for Prelim Chemistry.

**Topic: Concentration and Molarity**

*Manipulate variables and solve problems to calculate concentration, mass or volume using:*

*C=n/V (molarity formula)**Dilutions (number of moles before dilution = number of moles of sample after dilution)*

### Introducing The Molarity Formula C = n/V

Last post we introduced concentration, this video will go in a little more depth and introduce the **molarity formula** C=n/V (concentration = (moles of solute) / (volume of solution)).* (Note that this video spells litre like liter, don’t spell it like that.)*

This next video goes through the molarity formula as well, have a look if you’re still confused or to see if you can understand it in a different context.

### Dilution C1V1=C2V2

Recall the molarity formula, C=n/V, if we arrange this to make moles the subject: n = CV.

Now, let’s say an initial solution (1) has n1 moles (so n1 = C1V1), if the solution is **diluted,** which means more solvent is added, the same number of moles will be present in the final solution (2), which we can denote as n2 (so n2 = C2V2).

As the number of moles of the initial and final solution is the same, n1 = n2 and subsequently, C1V1 = C2V2, this is the **dilution formula**.

This video will take you through some dilution problems.

A form of dilution is** serial dilution** which is just many dilutions in a row, so a dilution on top of another dilution on top of another dilution. This video will explain a little more about serial dilution.