The Effect of Concentration on Reaction Speed | Chemical Experiment

When a piece of magnesium reacts with sulphuric acid bubbles of gas are formed. the piece of magnessium gets smaller and smaller until it "disappears". If we time how long it takes to dissappear we can get some idea of the reaction speed. The longer the time the slower the reaction speed. The speed of the reaction depends on various factors and in this experiment, we will look at one of these.

[b]Diagram[/b]

[img src="/blogs/img/gh_mg_h2so4_1010161305.jpg" /] [b]Chemical Equations[/b] Mg + H[sub]2[/sub]SO[sub]4[/sub] -> MgSO[sub]4[/sub] + H[sub]2[/sub] [b]Requirements[/b] 100cm3 glass beakers 50cm[sup]3[/sup] glass beaker 20cm[sup]3[/sup] syringe 10cm[sup]3 [/sup]syringe Timer Dilute sulphuric acid 2cm long pieces of clean magnessium ribbon deionised water

[b]Precautions and Care[/b]

Dilute sulphuric acid is corrosive and magnesium ribbon is highly flammable. When magnesiium reacts with sulphuric acid, an acid mist is formed which irritates the eyes and throat. Hydrogen gas is produced in the reaction and it is highly flammable because of these possible hazards you have to take care Wear safety glasses If any acid splashes on your skin, wash it off immediately Make sure there are no ignition sources around when you carry out the experiment When the magnesium reacts with the acid do not breathe in the acid mist When using the syringes always keep them pointing downwards

[b]Procedure[/b]

[li]Add dilute sulphuric acid to one of the 100cm3 glass beakers until it is half full. The acid has a concentration of 2 moles per litre. Record this concentration[/li]

[li]Using the 20cm3 syringe measure out 20cm3 of the acid into the 50cm3 glass beaker[/li]

[li] Add a piece of magnesium ribbon to the acid and at the same time start the timer[/li]

[li]When the magnesium has just "disappeared " stop the timer and record the time to the nearest second[/li]

[li]Wash out the small beaker and dry it[/li] [li]Repeat the experiment with 1 mole per litter sulphuric acid. To half the acid concentration from 2 moles per litre, add 10cm3 of the acid and 10cm3 of water to the small beaker[/li]

[li]Repeat the experiment one more time with 0.5moles per litre sulphuric acid[/li]

Contributed by Nuruddin Boateng - MBCS, MNZCS, MSc Information Technology, BSc(Hons) Chemistry, Dip Ed. To be continued.......