Aim:
To use a simple reaction between sodium thiosulphate and hydrochloric acid to discover concentration this determines how fast chemical reactions occur.
Independent Variable:
Concentration of hydrochloric acid (%)
Dependent Variable:
Time taken for chemical reaction to take place (sec)
Hypothesis:
My prediction is that the increased concentration of the thiosulfate will in turn lead to an increase in the rate of reaction. This is a well informed prediction as I know that one of the factors that speeds up rates of reaction is the increasing of the substrate, this increases the amount of particles that the hydrochloric acid can react with meaning that the reaction will go faster.
Constants:
Concentration of hydrochloric acid (%)
Apparatus and Materials:
Equipment:
Goggles
Reason: to protect my eyes against potential danger as hydro chloric acid is harmful and corrosive Why: I chose goggles because they cover a large precent of the investigators face and eyes and the school provides them for safety precautions.
Pen and paper
Reason: To write down the cross on the piece of paper so I can see when it disappears and the experiment finishes Why: This was one of the only things I could do to measure the time in which the flash gets fully translucent.
Pipette
Reason: To measure out the volumes of liquids and to accurately move them to where they need to be. Why: The pipette has very small markers on it and this makes it have a very high accuracy.
Measuring cylinder
Reason: This was also to measure.
Why: I used the measuring cylinder because it was big enough to hold anything I needed and was the only thing available.
Stopwatch:
Reason: This is needed because I am timing my experiment.
Why: It was either a clock or this, and I am certain that this is more accurate.
sodium thiosulphate (Na2S2O3)
Reason: Chemical needed for the