Lab Report
Investigation
Investigate the amount of heat evolved when magnesium reacts with dilute acids.
Planning
What I am going to do I am going to find out how much heat is given out when magnesium reacts with a variety of dilute acids. In order to make comparisons between the acids, I shall use my results to work out how much heat would be given out if 1 mole of magnesium reacted with an excess of each acid. The acids I shall use are hydrochloric acid, sulphuric acid, nitric acid and ethanoic acid. What I already know Magnesium reacts with most dilute acids to give a magnesium salt and hydrogen. For example: Mg + 2HCl Mg + H2SO4 MgCl2 + H2 MgSO4 + H2
I discovered from an A' level text book (A-level Chemistry by Ramsden) that nitric acid doesn't usually give hydrogen, but may do with magnesium if the acid is cold and dilute. The book didn't say how dilute the acid had to be. Other products may include oxides of nitrogen. I know that some acids are weak and some are strong. A strong acid is one which ionises fully in solution to give hydrogen ions and, for example, chloride ions or sulphate ions. Sulphuric acid, hydrochloric acid and nitric acid are all strong acids. Ethanoic acid is a weak acids. That means that its solution contains a high proportion of molecules that haven't split into ions. For all the reactions which give off hydrogen, the same ionic equation applies - whether the acid is strong or weak: Mg(s) + 2H+(aq) Mg2+(aq) + H2(g)
The key factors to vary, control or take into account The amount of heat given out will depend on the mass of magnesium I use - the more magnesium I use, the more of the above reaction happens. But because I am going to work out the amount of heat evolved per mole of magnesium, I don't need to take exactly the same mass for each experiment. I do, though, need to weigh the magnesium accurately for each experiment.
I am going to use an excess of each acid, so their exact concentrations don't matter. The amount of heat given
Investigate the amount of heat evolved when magnesium reacts with dilute acids.
Planning
What I am going to do I am going to find out how much heat is given out when magnesium reacts with a variety of dilute acids. In order to make comparisons between the acids, I shall use my results to work out how much heat would be given out if 1 mole of magnesium reacted with an excess of each acid. The acids I shall use are hydrochloric acid, sulphuric acid, nitric acid and ethanoic acid. What I already know Magnesium reacts with most dilute acids to give a magnesium salt and hydrogen. For example: Mg + 2HCl Mg + H2SO4 MgCl2 + H2 MgSO4 + H2
I discovered from an A' level text book (A-level Chemistry by Ramsden) that nitric acid doesn't usually give hydrogen, but may do with magnesium if the acid is cold and dilute. The book didn't say how dilute the acid had to be. Other products may include oxides of nitrogen. I know that some acids are weak and some are strong. A strong acid is one which ionises fully in solution to give hydrogen ions and, for example, chloride ions or sulphate ions. Sulphuric acid, hydrochloric acid and nitric acid are all strong acids. Ethanoic acid is a weak acids. That means that its solution contains a high proportion of molecules that haven't split into ions. For all the reactions which give off hydrogen, the same ionic equation applies - whether the acid is strong or weak: Mg(s) + 2H+(aq) Mg2+(aq) + H2(g)
The key factors to vary, control or take into account The amount of heat given out will depend on the mass of magnesium I use - the more magnesium I use, the more of the above reaction happens. But because I am going to work out the amount of heat evolved per mole of magnesium, I don't need to take exactly the same mass for each experiment. I do, though, need to weigh the magnesium accurately for each experiment.
I am going to use an excess of each acid, so their exact concentrations don't matter. The amount of heat given