I will make sure that my experiment is fair by using a different measuring tube and pipette for each chemical. I think that the rate of reaction between sodium thiosulphate and hydrochloric acid will increase as the concentration of the sodium thiosulphate solution increases.
I state this because by increasing the concentration you’re also increasing the amount of particles in the solution.
I will do this by timing how long it takes for the cross to disappear.
I will be measuring the quantity of sodium thiosulphate and hydrochloric acid I use, by using a ‘pipette’ and a measuring cylinder, which will allow me to precisely conduct my measurements.
I will then measure how long it takes for a chemical reaction to take place.
The time might vary depending on the concentration of Sodium thiosulphate.Disappearing Cross Investigation Aim: To see how long it takes for sodium Thiosulphate and hydrochloric acid to react at different concentrations.My Hypothesis: Using the idea of the particle theory, the more dilute a solution is, the more time it will take for the particles to react.Also, we need to wash the beakers and cylinders before using them as there could be another chemical left in the bottom.This could start off unwanted reactions and affect the reaction rate.Results/mins Acid/cm3Water/cm3Reaction Time 1Reaction Time 2Average Reaction Time2501.522.332.122052.092.432.2615102.242.542.3910153.053.383.215204.585.555.26/secs Acid/cm3Water/cm3Reaction Time 1Reaction Time 2Average Reaction Time250112153132.520512916314615101441741591015185218201.5520298355326.5Analysis/Conclusion We discovered that 25cm3 hydrochloric acid and 25cm3 sodium thiosulphate solution had the fastest reaction rate, just as we had predicted.English: ions in solution of hydrochloric acid Français : ions en solution dans l'acide chlorhydrique by Wikipedia.Then we drew a cross onto a piece of paper and put an empty conical flask on top of the paper.Next, we poured the 25cm3 acid and 25cm3 thio into the conical flask and started the stop clock.We timed how long it took for the solution to turn cloudy so that the cross could no longer be seen.We then decided to change the experiment to see if the concentration of the acid affected the rate of reaction.