Titration Calculations Flashcards

All 5 cards in this deck

What is the formula linking moles, concentration in mol/dm$^3$ and volume?

moles = concentration (mol/dm$^3$) × volume (dm$^3$)

How many cm$^3$ are there in 1 dm$^3$?

1000 cm$^3$ — divide a volume in cm$^3$ by 1000 to get dm$^3$.

What are the steps to calculate the concentration of an alkali from titration results?

e.g. 25.0 cm$^3$ of NaOH neutralised by 20.0 cm$^3$ of 0.100 mol/dm$^3$ HCl

1. Moles of acid = $\frac{20.0}{1000} \times 0.100 = 0.00200$ mol
2. Use the equation ratio (1 : 1): moles of NaOH = 0.00200 mol
3. Concentration = $0.00200 \div \frac{25.0}{1000} = 0.0800$ mol/dm$^3$

How do you convert a concentration in mol/dm$^3$ into g/dm$^3$?

e.g. 0.0800 mol/dm$^3$ NaOH ($M_r = 40$)

1. Multiply the concentration by the relative formula mass: $0.0800 \times 40 = 3.2$ g/dm$^3$

True or false? In every acid–alkali titration, the number of moles of acid equals the number of moles of alkali.

False. They are equal only if the balanced equation has a 1 : 1 ratio.