This is for a titration, to measure the amount of acid that can be neutralised by gaviscon. I know how to work out the first 3 but I'm not sure on the others.
I think i need to use the calculation c=n x v but i don't know where and why?
Theory. How do you work them out?
(i)Calculate the amount (in moles) of sodium hydroxide used in the titration
(ii)Write the balanced equation for the reaction between sodium hydroxide and hydrochloric acid
(iii)State the amount (in moles) of hydrochloric acid present in the 20cm³ sample used in the titration
(iv)Calculate the amount (in moles) of hydrochloric acid remaining in the solution made with the gaviscon tablet
(v)Calculate the amount (in moles) initially used to react with the tablet
(vi)Calculate the amount (in moles) of hydrochloric acid that reacted with the tablet
(vii)Assuming that the tablet contains an insoluble metal hydroxide, calculate the amount (in moles) of hydroxide ions present in each tablet
i)Calculate the amount (in moles) of sodium hydroxide used in the titration
mols NaOH = M x L
(ii)Write the balanced equation for the reaction between sodium hydroxide and hydrochloric acid
NaOH + HCl ==> NaCl + H2O
(iii)State the amount (in moles) of hydrochloric acid present in the 20cm³ sample used in the titration
<mols HCl = M x 0.020 L.
There isn't enough information given to calcualte the others. It appears that you added HCl (an excess) to the commercial tablet and back titrated with NaOH
(iv)Calculate the amount (in moles) of hydrochloric acid remaining in the solution made with the gaviscon tablet
(v)Calculate the amount (in moles) initially used to react with the tablet
(vi)Calculate the amount (in moles) of hydrochloric acid that reacted with the tablet
(vii)Assuming that the tablet contains an insoluble metal hydroxide, calculate the amount (in moles) of hydroxide ions present in each tablet
To solve these titration-related calculations, you will indeed need to use the formula c = n x v. Here's how you can apply it to each question:
(i) Calculate the amount (in moles) of sodium hydroxide used in the titration:
- First, determine the concentration (c) of sodium hydroxide, which is usually given in units like mol/dm³ or M.
- Next, convert the volume (v) of sodium hydroxide solution used in the titration to dm³ if necessary.
- Finally, plug in the values in the formula c = n x v. Solve for n to find the number of moles of sodium hydroxide used.
(ii) Write the balanced equation for the reaction between sodium hydroxide and hydrochloric acid:
- The balanced equation will show the stoichiometry of the reactants and products. For example, NaOH + HCl → NaCl + H2O. This equation tells us that one mol of NaOH reacts with one mol of HCl to produce one mol of NaCl and one mol of H2O.
(iii) State the amount (in moles) of hydrochloric acid present in the 20cm³ sample used in the titration:
- Given the volume of the hydrochloric acid sample used, convert it to dm³ if needed.
- Use the formula c = n x v to find the amount (in moles) of HCl. Rearrange the formula to solve for n.
(iv) Calculate the amount (in moles) of hydrochloric acid remaining in the solution made with the Gaviscon tablet:
- To determine the remaining HCl, you need to consider the reaction stoichiometry and the amount of NaOH used.
- Use the balanced equation from step (ii) to determine the stoichiometric ratio between NaOH and HCl.
- Then, calculate the number of moles of HCl that reacted with NaOH.
- Subtract this value from the total moles of HCl initially used to get the remaining moles.
(v) Calculate the amount (in moles) initially used to react with the tablet:
- Assuming the tablet reacted only with the HCl, you can use the same value obtained in step (iii) as the amount of HCl used to react with the tablet.
(vi) Calculate the amount (in moles) of hydrochloric acid that reacted with the tablet:
- This is the same value as the one calculated in step (v).
(vii) Assuming that the tablet contains an insoluble metal hydroxide, calculate the amount (in moles) of hydroxide ions present in each tablet:
- To find the amount of hydroxide ions, you need to determine the amount of NaOH used in the titration (step i).
- Use the balanced equation from step (ii) to determine that each mole of NaOH corresponds to one mole of hydroxide ions (OH⁻).