Concentrations

Imagine making hot chocolate. Mix a spoonful of cocoa powder into warm milk and stir until it dissolves.

But what if you add too much cocoa? The drink becomes thick and strong.

This happens due to concentration, the amount of a substance dissolved in a solution.

Here, cocoa powder is the solute, meaning it is the substance getting dissolved, and milk is the solvent, which dissolves the cocoa powder.

Adding more cocoa powder increases concentration because the liquid has more solute. Adding more milk makes the drink more dilute, meaning the cocoa is spread out more.

Concentration can be calculated by dividing the solute's mass by the solution's total mass and multiplying by 100.

Now, let’s find the concentration of cocoa powder in hot chocolate. If 20 grams of cocoa powder is mixed into 100 grams of milk, the total mass of the solution is 120 grams.

Dividing 20 by 120 and multiplying by 100 gives 16.67 percent. This means 16.67 percent of the solution is cocoa powder, while the rest is milk.