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Chemistry

GCSE

Calculate the relative formula mass of water.

The chemical formula for water is H₂O, and this means it contains 2 hydrogen atoms and 1 oxygen atom. If you then look at the periodic table and find the relative atomic mass for each element y...

Answered by Charlotte R. • Chemistry tutor

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Explain briefly the separation technique of fractional distillation, with reference to a particular example.

Fractional distillation is used to separate crude oil into its constituent fractions (e.g. petrol, naphtha etc. - names not required)Crude oil is heated to a high temperature and most is ...

Answered by Max H. • Chemistry tutor

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Potassium forms an ionic compound with sulfur. Describe what happens when two atoms of potassium react with one atom of sulfur. Give your answer in terms of electron transfer.

Electrons are transferred from potassium to sulfur. 2 potassium atoms each lose one electron forming K+ / 1+ ionsSulfur atoms gain 2 electrons forming S2- / 2- ions. This results in the ionic formula K

Answered by Mariam B. • Chemistry tutor

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Describe the bonding between sodium and chlorine in NaCl

Sodium donates its outer shell (valence) electron to chlorine, so that both have a full outer shell. Sodium and chlorine are then held together by electrostatic forces of attraction between the positively...

Answered by Sarah B. • Chemistry tutor

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Describe the trend in reactivity as you go down group 2 metals?

As you go down group 2, the reactivity increases as the atomic radius increases and the shielding increases. This is despite the increase in nuclear charge. Therefore, as you go down group 2 less energy i...

Answered by Chioma N. • Chemistry tutor

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