Coursework: Effect of Temperature on the Rate of Reaction between

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Coursework: Effect of Temperature on the Rate of Reaction between

Sodium Thiosulphate and Hydrochloric Acid

Investigation

Chemical reactions are used in our everyday life, they literally keep us alive. They are used in food, respiration and everywhere else in the environment. A chemical reaction mainly occurs when reactants react together to produce a new product. The speed at which this reaction takes place is called the rate of reaction. The product produced has a number of particles in the solution that has formed from the reactants. The concentration is the amount of particles in a certain amount of water. If a cross is placed under the beaker of the solution, the cross will eventually disappear because the high temperature of the water will make the particles move faster because they have more energy and they will move more quicker to give a bigger impact which will cause more frequent and violent collisions and the solution will disappear as the product forms to create a misty solution. The rate of reaction is normally recorded in tables and can then be defined onto graphs to show how the rate curves of different factors affect the speed of the reaction. A rate curve is the curve of a graph that shows how the reaction changes at different intervals. The gradient of the graph tells us whether the different rate curves have the same relation, meaning if they have a similar rate of reaction. Reactions can take place in a variety of customs; they can bee steep or steady. The steeper the slope, the faster the reaction takes place. The steadier the slope, the slower the reaction takes place.

Aim:

 The aim of my investigation is to find out whether the increase of temperature increases the rate of reaction between the two reactants of Sodium Thiosulphate and Hydrochloric acid. I will then find out and evaluate on how temperature affects this particular reaction.

Factors

There are four main factors, which affect the rate of reaction that are considered as variables for the experiment I will be doing, they are the following: Molecules can only collide when two of them meet together. This meeting between the two particles can only take place on the surface area of the material. If the surface area of the material is increased, the particles gather more space to collide with each other with force. With a large surface area, the particles will have more area to work on so the collision probability will be high. A catalyst is a separate substance to the ones you use in your experiment and is used to speed up the reaction between the reactants. Only a minute amount of the catalyst is required to produce a dramatic change in the speed of the reaction. This is mainly because the reaction proceeds by a different pathway when it is added compared to a normal reaction without a catalyst. The catalyst basically gives the reacting particles a surface to stick onto so it is easier for particles to collide with each other as some particles will be stuck onto the surface area of the catalyst and moving particles can collide with them easier and faster. After the reaction takes place, the catalyst is left behind. The catalyst makes absolutely no difference to the end product; it only changes the speed of the reaction. Temperature is the indicator of heat. This gives the particles energy to move around faster, which will lead to them roaming the solution with force and there would be a more likely chance of collision. Two reactant molecules will only be able to react if they have enough energy. The temperature increases the energy levels involved in your reaction and causes them to collide violently. This collision theory is also known as the kinetic theory as molecules are moving with their energy. The concentration is the amount of particles in a certain amount of water. Increasing the concentration is increasing the amount of particles inside the water so there is a more likely chance of collisions to take place.? Also, when the concentration is increases, the important particles are more close together because there are plenty of reactant particles so they can collide easily. The pressure is increased once the volume of the solution is reduced. This is putting more pressure onto the existing amount of particles as there is a smaller space to move around so there is more of a chance of a collision. This will mean that increasing the pressure will increase the rate of reaction. The most useful variable is temperature. This is because if the particles gain energy from the temperature, the probability of collision will be high. This will suit my investigation as I will be looking at what extent the temperature helps the reaction the most and least

Prediction & Scientific knowledge

Based on my knowledge of general reactions, I believe that as the temperature is increased, the rate of reaction will also increase. I think that the rate of reaction purely depends on the temperature as the temperature is the factor that gives the reacting particles energy to move about quicker and collide more violently and frequently. Reactions can only take place if the particles collide with enough energy. Temperature can help this take place so the higher the temperature; the faster the particles will collide (with more impact). This will give you a faster rate of reaction.

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The reaction will only occur where the particles of the reactants meet and combine together. The collision theory also states that as you increase the rate of reaction, the collisions between particles are bound to increase vastly. A general reaction consists of collisions between molecules or atoms that have the ability to react in response to collisions. The bonds between atoms are formed in such a way that it requires the atoms to stay close together. If one group of atoms is to from a new bond with another, it can only be done if the atoms are close enough ...

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