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Chemistry

A Level

An amino acid contains 52.2% carbon, 9.3% hydrogen, 8.7% nitrogen and 29.8% oxygen by mass and has a relative molecular mass of 161 g/mol. What is its molecular formula? What functional groups must it have?

In 100g of compound, the amount of each element is given by: C: n = 52.2/12 = 4.35 H: n = 9.3/1 = 9.3 N: n = 8.7/14 = 0.621... O: n = 29.8/16 = 1.8625 Dividing through by the smallest amount (0.621) gives...

Answered by Georgina B. • Chemistry tutor

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Describe and explain the difference in base strength between ammonia, primary aliphatic and primary aromatic amines.

Alkyl groups increase basicity because: 1) They push electron density onto the nitrogen atom, which makes the nitrogen lone pair more attractive to hydrogen ions. 2) They stabilise the positive charge on ...

Answered by Sophie B. • Chemistry tutor

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State the crystal structures of SiO2 and CO2 and why one has a higher melting point than the other.

SiO₂ forms a giant covalent structure while CO₂ has a simple molecular structure.In the giant covalent structure of SiO₂, strong covalent bonds hold the atoms together in...

Answered by Fabian T. • Chemistry tutor

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Rank the following acids according to acid strength, strongest to weakest: HF, HCl, HBr. Explain your reasoning.

Answer: HBr, HCl, HF
Firstly, we must understand what is meant by "acid strength". Simply put, it's the concentration of "free" hydrogen ions (H+) in solution. Acids dissociate (...

Answered by Edgar K. • Chemistry tutor

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Why is a water molecule non-linear?

Valence Shell Electron Pair Repulsion Theory (VSEPR) states that lone pairs repel other lone pairs more so than they do bonded pairs. In water, the oxygen atom has two lone pairs. These two lone pairs rep...

Answered by Harry M. • Chemistry tutor

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