Investigate 'How much gas is released when a metal reacts with an acid.'

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Alisha Meertins                Mr Skidmore

Chemistry Coursework

Planning

  In my experiment, I am going to investigate ‘How much gas is released when a metal reacts with an acid.’

  When I do the experiment, there will be many hazards that I will have to face and control so that there are no dangers to others or myself.  First, I will have to wear my laboratory coat and safety glasses, as this is a compulsory obligation that must be undertaken in order to decrease the amount of accidents that can happen to the skin and eyes.

  I will have to be careful when handling the acid as acid is an irritant and can therefore cause injury easily, if spilt on someone’s hand, for example.  In order to keep the number of injuries to a minimum I will not carry acid around the classroom and I will make sure that any container holding acid is nowhere near the edge of a table or somewhere that it can be knocked off.  If I do spill some of the acid I will alert the teacher to make sure that it is safe for me to clean it up.

  As well as this, I will have to be careful when using glass products, which will be quite frequent in this experiment.  Glass can very easily be broken and can cause people to cut themselves quite deeply and if it gets into the eyes, it can cause blindness, in extreme cases.  In order to keep the breaking of class to a bare minimum I will make sure that my hands are dry when carrying it so that it does not slip out of my hands.  I will look where I am going as I move around the classroom when I am carrying glass so as not to bump into anyone and drop the glass as a result, and I will not keep glass near the edge of any tables as it could easily be knocked of if I do.

  Furthermore, I will have to be particularly careful with the measuring cylinder for it is glass but also because if it is attached to the clamp to tightly the and too low into the ice cream tub of water the rubber delivery tube might get caught and blocked which could cause an explosion.  In order to stop this happening, I will have to make sure that the delivery tube is not blocked and the measuring cylinder is not clamped too tightly and that it is not too low into the water in the ice cream tub.

  I think that the amount of gas released will be in proportion with the amount of metal used.  For example, if:

0.50g of metal was used and 100cm³ of gas was produced

When

0.25g of metal was used; 50cm³ of gas would be produced

And when

1.00g of metal was used; 200cm³ of gas would be produced.  

  In order to find out how much gas will be produced when a certain amount of metal is added, I will us ‘The Mole Theory’.  The first part of doing this is to find out how many moles there are in Magnesium, which is the metal I am going to be using.  To do this, this equation must be used:

Number of moles = mass ÷ mass of 1 mole

  In this case, when I substitute the writing in the equation with the correct numbers I will get:

Number of moles = 24 ÷ 24

Number of moles = 1

  The way in which I got this answer is that I know that the Relative Atomic Mass of Magnesium is 24 and that there are no other metals in Magnesium.  This means that the formula mass is 24 and therefore the mass of 1 mole is 24g.  Therefore, I already know that 1 mole is 24g of Magnesium; however, I did the equation as a check.

  After doing this you use the chemical equation for the reaction, in my case it will be the reaction of Magnesium with diluted Sulphuric Acid:

Mg     +     H2SO4                              MgSO4    +    H2   

  As Magnesium is only one mole and weighs 24g, the gas that is produced by the reaction of the Magnesium with the acid should occupy 24l (24000cm3) at room temperature and pressure.  I know this because due to Magnesium being one mole and 24g it produces 1mole of hydrogen gas and all gases that are 1 mole occupy 24l.  It is a rule.  Knowing this makes it easy to work out how much Hydrogen will be produced when different amounts of Magnesium is used because as:

24g of Magnesium will make 24L of Hydrogen (24000cm³),

0.24g of Magnesium will make 0.24L of Hydrogen (240cm³), and

0.024g will make 0.024L of Hydrogen (24cm³)

  This pattern goes on and this is how I will justify whether my prediction is correct.

  The amount of acid that I use in the experiment is also important, as this is also one factor that will vary how much gas will be produced due to the reaction.  The equation for the reaction that is going to take place is:

Mg     +     H2SO4                              MgSO4    +    H2 

    In addition, the amount of acid needed for my largest amount is going to be this:

Mg     +     H2SO4                              MgSO4    +    H2 

  I got this in the same way as I showed above to find out how much Hydrogen Gas would be produced when a certain amount of Magnesium was used.

  The Atomic mass of ‘H2SO4’ is 98g.  This is 2 (the mass of H2) + 32 (the mass of the sulphur) + 16 × 4 (the mass of the 02).  You then work out how much you will need for a certain amount of Magnesium:

24g of Magnesium will need 98g of H2SO4

0.24g of Magnesium will need 9.8g of H2SO4, and

0.024g will need 0.098g of H2SO4.

  We used more than this, we used 20ml.  This is because 0.98g is too small to measure and is not the right amount to react for the other masses of magnesium.  20ml is an easy amount to measure and is the right amount to react with all the masses of magnesium.

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  In the preliminary experiment, I will use the smallest amount of Magnesium that can be used, which is 0.024g, and the largest amount of Magnesium that can be used which is 0.24g.  I will use these two amounts just to see whether I am doing the experiment accurately and correctly and to see whether my results are following the pattern.

   Therefore, to do the preliminary experiment I will weigh the amount of Magnesium I am going to use.  I will do this as accurately as possible by making sure that I when I weigh the magnesium it ...

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