Na2 + S2 + 2HCL 2NaCl+SO2 + S2 +H2O

To time the reaction I will draw a black cross on a piece of plain paper on which the beaker of reactants will be placed (HCL and Thiosulphate). When the chemicals come into contact with each other I will start timing with a stopwatch and will stop timing when the cross is longer visible through the beaker from above.

A chemical reaction between to chemicals can only happen if their molecules can collide into each other. Out of many collisions there will be a few successful collisions, which means that the two molecules will exchange electrons and that means that they have reacted. These molecules have to hit each other in the right direction and at the right speed; in short the rules for a "successful collision" are specific and complex. But if the number of c

Concentration of a reactant affects reaction rate because there are more frequent successful collisions.

ollisions per second increase so will the number of successful collisions increase. This means that the rate of the reaction has increased. For a reaction to occur you also need the required activation energy which means that if there isn't enough the reaction won't take place although catalysts can lower this.

As you can see only 2 molecules can react with 2 HCL molecules. But if there was less water this happen:

Some common words found in the essay are:
Average Rate, Volume H20, Concentration Concentration, Apparatus Stop-watch, Catalyst Activation, HCL Thiosulphate, Light Temperature, , reaction rate, S2 O2, rate reaction, measuring cylinder, successful collisions, percentage thiosulphate, stop timing, input variables, straight line, concentration thiosulphate, cm 3, increases reaction rate, Catalyst Concentration, affects reaction rate, volume cm 3, molecule decreases 50%, foreign molecule decreases,
Approximate Word count = 3270
Approximate Pages = 13 (250 words per page double spaced)