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 Chromatography: 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.

96%

114 rated

Answer

The error made by the student was that the spots of ink were placed below the solvent level. This means that the ink spots would not dissolve into the solvent and move up the chromatography paper as intended. For effective separation, the spots must be above the solvent level.

Step 2

Show outer electrons only.

99%

104 rated

Answer

The Lewis structure for methane (CH₄) displays the outer electrons as follows:

      H
      |
  H - C - H
      |
      H

In this diagram, the carbon atom shares one pair of electrons with each of the four hydrogen atoms, resulting in four single covalent bonds.

Step 3

Explain why diamond has a very high melting point.

96%

101 rated

Answer

Diamond has a very high melting point due to its strong covalent bonds and large number of bonds in its giant lattice structure. Each carbon atom in diamond is tetrahedrally bonded to four other carbon atoms, creating a strong network. A lot of heat energy is required to break these strong covalent bonds, which contributes to its 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.

Join the GCSE students using SimpleStudy...