Rates of Reaction Experiment
Introduction/Aim:
This coursework is about the investigation of the effect of
concentration on the rate of reaction between Sodium Thiosulphate (Na2S2O3)
and Hydrochloric acid (HCL) by simply changing the concentration of
Sodium Thiosulphate. I made a set of results which were obtained by
using the method of 'precipitation'. This is when the product of the
reaction is a precipitate, which clouds the solution. One observes a
marker through the solution and measures how long it takes for it to
disappear.
Plan:
In order to make it a fair test the volume of hydrochloric acid had to
be kept constant each time (5cm³). What had to be changed was a) the
amount of Sodium Thisulphate and b) the amount of water. We decided
our total volume to be 55 cm³, 5 cm³ of that hydrochloric acid, so the
rest consisted of Sodium Thisulphate and Water. To obtain our resultes
we used the following "Method":
Step 1:
After setting up everything we first used a measuring cylinder to
measure the amounts of Sodium Thiosulphate, Water and Hydrochlorid
acid needed. We put the added amount of water and thiosulpahte (which
has to be 50 cm³) into a connical flask which will be placed on a
paper marked with a cross ("X").
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After that we take the measuring cylinder with the 5 cm³ of HCl and
pored it into the conical flask.
Step 2:
The stopwatch was started as soon as the first drop of HCl got in. We
did this in order to estimate the time how long it took until the
reaction was comletet. The mixed solution was first clear, but as time
went by it got gradually more and more cloudy because of the many
reactions taking place in the solution. so that´s why we started to
take the time when the solutions were just mixed together until a
point, where the mixed solution has reached a point, where the
solution has a specific 'cloudiness' and we couldn`t see the cross
this is the best volume to use as it is about ¾ of a test tube full,
Measure the weight of a small stone to fit inside the opening of a 50ml graduated cylinder.
I am going to investigate how the concentration of hydrochloric acid alters the rate of reaction. As I increase the amount of water, I
ranging from 50 cm³ of acid and no water, to 12.5 cm³ of acid and 37.5
The first step that we took to accomplish our goal was to put on our safety goggles and choose a lab station to work at. We received one 400ml beaker, one polyethylene pipet, two test tubes with hole rubber stoppers, two small pieces of magnesium (Mg), one thermometer and a vial of hydrochloric acid (HCl). We took the 400ml beaker and filled it about 2/3 full of water (H20) that was 18 OC. Then we measured our pieces of Mg at 1.5 cm and determined that their mass was 1.36*10-2 g. We filled the pipet 2/3 full of HCl and poured it into one of the test tubes. Then, we covered the HCl with just enough H2O so that no H2O would be displaced when the stopper was inserted. After inserting the stopper, we placed the Mg strip into the hole, inverted the test tube and placed it in the 400ml beaker. HCl is heavier than H2O, so it floated from the tube, into the bottom of the beaker, reacting with the Mg along the way to produce hydrogen gas (H2). We then measured the volume of the H2, cleaned up our equipment and performed the experiment a second time.
= = = == I predict that as the concentration of the hydrochloric acid decreases the rate of reaction will decrease and therefore the time taken for 75ml of gas to be released will increase.
The aim of the experiment is to titrate a strong acid and a weak acid with a primary standard
This is very important as changing the volume can have a negative effect on your experiment and report. Make sure that you use 10cm3 of hydrochloric acid throughout all the 5 trials, You can measure the volume with help of a measuring cylinder or you can also use a pipette to measure it accurately
and set the up to one of the stands and then measure out 30ml of
...ations served as background information for the calculations and for the general procedure of the lab. The solid acid, when added to water ionized to form charged particles causing the solution to have a certain pH that could be figured out from a titration curve graph. The acid used in this lab, KHP, ionized in water and formed Hydronium ions in the water. These ionized particles were what gave the acid a certain pH and those particles were what was being neutralized in the reaction. Multiple titrations were performed to neutralize the acid, in each titration, the lab groups attempted to reach the exact endpoint of the reaction without going over it. The endpoint was indicated by a slight color change in the solution to a pale pink color. When the endpoint was achieved, the calculations for the moles of acid to the moles of base were equal at that point.
The amount of hydrochloric acid. 3. The concentration of the hydrochloric acid. 4. The surface area of the calcium carbonate.
3.0g of salicylic acid was weighed (salicylic acid was formed from Step 1) into a 100mL beaker. In a 10mL graduated cylinder, 5.0mL of acetic anhydride was measured and was transferred into the 100mL beaker. 5 drops of concentrated sulphuric acid was also added into the beaker.
measure the time of the reaction, so we can make a rate for it, to do
second test tube also add 6 mL of 0.1M HCl. Make a solution of 0.165