Some students were asked to separate and identify the dyes in four inks, W, X, Y and Z. One student put a drop of each ink onto a line on chromatography paper and set up the chromatography apparatus as shown in the diagram. Explain the error made by the student when the apparatus was set up. (c) Methane has the formula CH₄. A carbon atom has four electrons in its outer shell. A hydrogen atom has one electron in its shell. Show outer electrons only. (d) Diamond has a giant molecular, covalent structure. The diagram shows part of the structure of diamond. Explain why diamond has a very high melting point.

GCSE Edexcel Chemistry Diamond: Some students were asked to sepa

Some students were asked to separate and identify the dyes in four inks, W, X, Y and Z - Edexcel - GCSE Chemistry - Question 3 - 2018 - Paper 1

Question 3

Some students were asked to separate and identify the dyes in four inks, W, X, Y and Z. One student put a drop of each ink onto a line on chromatography paper and s... show full transcript

Worked Solution & Example Answer:Some students were asked to separate and identify the dyes in four inks, W, X, Y and Z - Edexcel - GCSE Chemistry - Question 3 - 2018 - Paper 1

Step 1

Explain the error made by the student when the apparatus was set up.

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Answer

The error made by the student is that the spots of ink should be placed above the level of the solvent in the chromatography apparatus. This is important because if the spots are below the solvent level, they will dissolve directly into the solvent and will not separate along the chromatography paper.

Step 2

Show outer electrons only.

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Answer

The outer electron configuration of methane (CH₄) can be represented as follows:

   H
   |
H--C--H
   |
   H

In this structure, the carbon atom (C) shares its four outer electrons with four hydrogen atoms (H), thus forming four covalent bonds.

Step 3

Explain why diamond has a very high melting point.

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Answer

Diamond exhibits a very high melting point due to its strong covalent bonds and large number of bonds. Each carbon atom forms four strong covalent bonds in a three-dimensional lattice structure. This lattice requires a substantial amount of energy to break the bonds, which contributes to diamond's high melting point.

Some students were asked to separate and identify the dyes in four inks, W, X, Y and Z - Edexcel - GCSE Chemistry - Question 3 - 2018 - Paper 1

Worked Solution & Example Answer:Some students were asked to separate and identify the dyes in four inks, W, X, Y and Z - Edexcel - GCSE Chemistry - Question 3 - 2018 - Paper 1

Explain the error made by the student when the apparatus was set up.

Show outer electrons only.

Explain why diamond has a very high melting point.

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