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Investigating the Relative Atomic Mass of Lithium

Satisfactory Essays
Investigating the Relative Atomic Mass of Lithium

Background information

I’m going to produce a piece of coursework, which determine the

relative atomic mass of lithium.

Two methods are going to be used to approximate the relative atomic

mass of lithium.

1) In the first method the RAM (Relative atomic mass) of lithium is

determined by the Volume of hydrogen gas produced.

2) In the second method the RAM of lithium is determined by titrating

the lithium hydroxide produced.

To some extend, I think that the first method is the most practical

and less complicated, because the less calculations has to be done.

Hence it is more easer to measure the volume of hydrogen gas.

Test-1

My mission was to find out the atomic mass of lithium. I took a sample

and weighted it, removed parts of the sample so that it would weigh

approximately 0.100g. The oil was removed from the sample by filter

paper wiping it with,so no more oil can be seen. The scale was not a

very sensitive one and we could weigh with a margin of error of 0.01g.

Then I placed the sample in a beaker that contained 100 cm3 of

distilled water. Then after a while we so bubbles, which confirmed

that a reaction was taking place.

The reaction will look like this:

2Li (s) + 2H2O(l) ---à2LiOH(l) + H2(g)

But since the distilled water was in excess there will also be a lot

of H2O and OH in the beaker and the solution will therefore be a

hydroxide solution.

The next thing to do was measure the volume of hydrogen gas produced.

The calculate of R AM of lithium; will be done in results.

Test-2

My mission was to find out the atomic mass of lithium. But this time

by titrating the lithium hydroxide with HCl.

From the solution that I have created in test-1 I pipette 25cm into a

conical flask, then 5 drops of phenolphthalein indicator was added.

The solution turned pink - The next thing to do was to put to put the
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