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.
A student put a drop of each ink onto a line on chromatography paper and set ... 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 student made the error of placing the ink spots below the solvent level. This means that the ink spots will not dissolve into the solvent and thus will not move up the chromatography paper as intended.
Step 2
Show outer electrons only
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Answer
The outer electrons of methane (CH₄) are as follows:
Each hydrogen atom has one electron, depicted as:
H
|
H - C - H
|
H
The carbon atom has four electrons, and one of those is shared with each of the four hydrogen atoms, represented as four single bonds.
Step 3
Explain why diamond has a very high melting point
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Answer
Diamond has a very high melting point due to its strong covalent bonds and large number of bonds per carbon atom. Each carbon atom forms four strong bonds in a three-dimensional lattice structure, requiring a large amount of heat energy to break these bonds, thus resulting in a high melting point.
