Which of the following acids, when added into 50cm³ of 0.01mol dm-3 of sodium hydroxide solution, produce the same rise in temperature of the mixture?
I. 50cm³ of 0.01mol dm-3 hydrochloride acid
II. 25cm³ of 0.01mol dm-3 sulphuric acid
III. 50cm³ of 0.01mol dm-3 nitric acid
IV. 50cm³ of 0.01mol dm-3 ethanoic acid
Answers
Answer:
Titration calculations - Higher
The results of a titration can be used to calculate the concentration of a solution, or the volume of solution needed.
Calculating a concentration
Worked example
In a titration, 25.0 cm3 of 0.100 mol/dm3 sodium hydroxide solution is exactly neutralised by 20.00 cm3 of a dilute solution of hydrochloric acid. Calculate the concentration of the hydrochloric acid solution.
Step 1: Calculate the amount of sodium hydroxide in moles
Volume of sodium hydroxide solution = 25.0 ÷ 1,000 = 0.0250 dm3
Rearrange:
Concentration in mol/dm3 =
Amount of solutein mol = concentration in mol/dm3 × volume in dm3
Amount of sodium hydroxide = 0.100 × 0.0250
= 0.00250 mol
Step 2: Find the amount of hydrochloric acid in moles
The balanced equation is: NaOH(aq) + HCl(aq) → NaCl(aq) + H2O(l)
So the mole ratio NaOH:HCl is 1:1
Therefore 0.00250 mol of NaOH reacts with 0.00250 mol of HCl
Step 3: Calculate the concentration of hydrochloric acid in mol/dm3
Volume of hydrochloric acid = 20.00 ÷ 1000 = 0.0200 dm3
Concentration in mol/dm3 =
Explanation: