Aim: investigating making Epsom salts by varying the rates of reaction. Research: Reaction with Dilute Acid: Potassium, sodium, lithium and calcium all react violently with dilute H2SO4(aq) and dilute HCl (aq). The reaction is similar to the reaction with water, forming the metal salt (either sulphate or chloride) plus H2(g). Magnesium, aluminum, zinc, iron, tin and lead react safely with dilute acid, magnesium is the fastest and lead is the slowest of the six. Magnesium + sulphuric acid magnesium sulphate + hydrogen.

There are many different uses for Epsom salts (magnesium Sulphate) When magnesium sulphate is absorbed through the skin, such as in a bath, it draws toxins from the body, sedates the nervous system, reduces swelling, relaxes muscles, is a natural emollient, exfoliate, and much more. Epsom salts can be used for many things such as:  Relaxing and Sedative Baths Face Cleaner  To make Homemade Skin Masks  To soak feet  To exfoliate skin  Remove Excess Oil from Hair  Hairspray  Hair Volumizer  Soak Sprains and Bruises  And to remove splinters.

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This piece of information was obtained from www. askjeeves. com ——care2. com. Epsom salts is the name originally given to hydrated magnesium sulphate, MgSO4. 7H20 . Millions of people all over the world have asked for Epsom salts, and used it with recognisable effect, without knowing anything about Epsom. The reasons for the efficacious action of Epsom salts were not known until a long time after its discovery, and magnesium as an element was not discovered until nearly a century later. This piece of information was obtained from www. askjeeves. com

The bonds between magnesium and sulphate has a lot to do with the rates of reaction and how different variables affect the substances so here is some information about the rates of reaction: Some chemical reactions are fast others are slow. The reactions go at different speeds or rates and this is often dependant on the variable or variables that are used on the metal. There are various rates that we are able to vary such as:

The temperature – by using temperature as a variable you are able to control the reactions. If you increase the temperature by 10 i??then you would expect the chemical reactions to work at twice the rate because raising the temperature makes the particles in the sulphuric acid to move twice as fast which would increase the number of times that the particles collide with each other. If the temperature is reduced then this would slow down the reaction process as this would mean that the particles are less energetic as they are not being heated up so that they collide more often this would result to less reaction being given off in this case less hydrogen would be produced.

The concentration – the concentration affects the rate of reaction, as the more concentrated the solution is the more stronger the solution is which would mean that the substance i. e. sulphuric acid is more concentrated relieving more power which would mean that the reaction would be stronger and greater than a weaker solution. Increasing the concentration would also mean that there would be more particles per dmi??

, and the more particles there are the more they would collide per second which would release a greater reaction. However decreasing the concentration will lead to the opposite effect of that of a higher concentration, there would be less particles per dmi?? which would result in a less reactant solution. Also the more concentrated the solution gets or the less used of it would mean that the solution gets weaker and less able to produce a energetic reaction.

Increasing the surface area – if the surface area is increased then in theory this would just mean that there would be a greater amount of this substance as there is more space for the substance, this would mean an increase in acid which would mean a greater reaction if the surface area is decreased then the reaction would be limited as thee is less solution to react the metal with.  Increasing pressure – if gases are being reacted with then increasing the pressure of this gas would mean that there would be more particles per dmi??.

This again reflects back onto the collision theory about the more particles there are the more will collide per second which would mean that the rate of reaction would increase.  A catalyst – A catalyst (strictly speaking) will change the rate of reaction. A catalyst can make a reaction go faster or slower. In practice, a catalyst is mainly used to make a reaction go faster a catalyst works by providing a convenient surface for the reaction to occur.

The reacting particles gather on the catalyst surface and 1) collide more frequently with each other,2) more of the collisions result in a reaction between particles because the catalyst can lower the activation energy for the reaction. A catalyst is often used as a powder, so that it has a bigger surface area per gram I have now discussed all the variables that I am able to use in my experiment of making Epsom salts and how different actors would affect this process. I am now going to talk about the collision theory as the collision theory is the main theory behind all these variables:

The collision theoryThe collision theory is basically when particles react to produce a reaction. Reactions occur when the particles are facing the correct direction and when there is enough energy present to make the reaction. The more collisions between the particles and the harder they hit each other means the higher the reaction rate. There are many ways in which to increase the reaction rate for example to increase the temperature. Below is a diagram of how the particles will look if the temperature is cold and how the particles move when the temperature is hot.

As you can see where the temperature is colder the particles are less energetic and not that close together which means that it takes a longer time for them to collide and with a decrease amount of force applied as they have less energy inside them to give out. Whilst where there is more heat applied the particles have more energy leading to frequent and harder collisions between the particles which means that they can release more energy and the reaction process would occur at a faster rate.

The other aspect that affects the collision rates is the concentration (or pressure), if the solution is more concentrated it means that there are more particles of reactants knocking about between the water molecules which makes the collisions between the important particles frequent and likely to occur. The diagram below shows you this: As you can see the high concentration area has more particles which means that they are more likely to collide frequently releasing more energy, whilst the low concentration has less particles meaning it would take longer for the particles to reach each other to collide.

In a gas the increasing of pressure means that more particles are present which means that they are squashed up, again this relates to the more particles the more the greater the chances are of collision. Another aspect that affects collision rates is catalysts. Catalysts increased the number of collisions. A catalyst works by giving the reacting particles a surface to stick to where they can bump into each other. The greater amount of catalysts used the more elements the particles have to stick onto increasing the rate of collision.

The diagram below explains what I am trying to say: In theory not all collisions bring about a chemical change, meaning it does not necessary work. A collision may be affective in making a chemical. This was the collision theory. I am now going to start writing up my investigation. This investigation is basically to find out how in the process of making Epsom salts (magnesium sulphate MgSo4) different variables would affect it, in my case it would be how the levels of hydrogen gas would be affected as I am going to be varying the concentration of sulphuric acid.

I have decided to choose to vary the concentration because after looking at the variables that I am able to differ I thought that varying the concentration would be the safest option. Below I have listed the risk assessments of all the elements that I am going to use in this investigation:  Sulphuric acid – is very corrosive. It can cause server burns. The solution is equal to or stronger than 1. 5m. Fuming sulphuric acid (0leum) is more hazardous as the fumes of sulphuric acid are very dangerous to the human system.

This is not recommended for use in schools. Suphuric acid is also dangerous with water, hydrochloric acid, chlorides, hydrogen chloride, phosphorous, sodium, potassium and many other metals as dangerous reaction can take place. If swallowed: you should wash out mouth and drink glasses of water. Do not induce vomit and then seek medical help. If splashed in eye: care should be taken when handling this acid as it is a very corrosive solution.

If in contact with eye then make sure you flood the eye with tap water for 10 minutes and then seek medical attention. If splashed on skin or clothes: if the acid spills on your skin then wipe as much of the acid off with a dry cloth and then drench affected area with large excess water. If skin starts to blisters then seek medical attention immediately. If the acid is spilt on clothing then remove contaminated clothing and pay attention to the skin if solution has seeped through then follow the methods of above.

Magnesium  Magnesium sulphate  Hydrogen gas So by looking at all the risk assessments of the above elements I think it is wise not to use the temperature as the variable because if sulphuric acid is heated up then it will create fumes which is not ideal to do as it is very dangerous to us and it is not practical to heat it up in a school laboratory it would be alright if we were in a professional laboratory with the correct high-tech equipment to protect ourselves and to conduct the experiment properly.

It is also not ideal to use temperature as if acids are heated up they usually splash out, and due to the risks of the sulphuric acid has on the skin it would not be ideal to heat it up because if we do heat it up then we are literally looking at casualties. Another reason not to use temperature is that both magnesium and hydrogen are highly flammable and it is not a good idea t have them around naked flames after knowing this.

I could vary the surface area, so this would basically mean to use different amounts of magnesium metal to see what the affect of having more or less metal has to do with the amount of hydrogen produced, but the reason that I am not going to do this is because it would not be a fair test as the amount that I will increase or decrease would not be able to be constant.

Also it is not qualitied, I will not be able to get qualited results by using the surface area which means that when I draw my graphs I will not be able to draw line graphs which I need for I will only be able to draw bar charts due to the type of results that I would receive. I can not increase the pressure because you are only able to increase the pressure of a gas and as I am not using a gas element I the practical I can not vary this. I am producing a gas. I can also vary the catalyst but this would be the same as the surface area or varying the mass of magnesium.