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What is the best way to structure answers to evaluation questions (24 marks)?

For longer answer questions, examiners want to see you demonstrate a higher level of analysis and evaluation. The short mark answers rely solely on knowledge but the longer marks require you to do more with ...
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Answered by Kajal P. • Geography tutor
32520 Views

(a) By using a suitable trigonometrical identity, solve the equation tan(2x-π/6)^2 =11-sec(2x-π/6)giving all values of x in radians to two decimal places in the interval 0<=x <=π .

say (2x-π/6)=qtan 2 q = sec 2 q-1so sec 2 q-1= 11 - sec q sec 2 q + sec q -12 = 0(sec q -3) (sec q + 4) = 0sec q = 3 or -4because 0&lt;=x&lt;= πso -π/6 &lt;= q &lt;= 11π/6q = 1.23 or 1.82 or 4.46 or 5.05so x...
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Answered by Zhaohui Z. • Maths tutor
9172 Views

Describe the changes in equilibrium of ethanol production from ethene and water (enthalpy of reaction is ∆H = - 46 kJ/mol) when: (a) a high pressure is applied; (b) ethanol concentration is increased; (c) temperature is increased; (d) a catalyst is used.

The equation for the reaction (would be given for this type of question but I ran out of space): C 2 H 4 (g) + H 2 O (g) ⇌ C 2 H 5 OH (g) ∆H = - 46 kJ/molQuestion is based on Le Chatelier's principle: if a s...
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Answered by Aiste A. • Chemistry tutor
8561 Views

Using principles of structure and bonding, explain why sulfur has a higher melting point than phosphorus

Sulfur, which is naturally S 8 has more electrons than Phosphorus, which is naturally P 4 . Therefore the Van der Waals between molecules is stronger in Sulfur than it is in Phosphorus, so more energy is req...
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Answered by Dalvin S. • Chemistry tutor
32601 Views

There are 895 litres of petrol in Mr Turners petrol tank, he uses 19.7 litres of petrol a day. Estimate the number of days it will take him to use all the petrol in the tank.

895 is approximately 90019.7 is approximately 20 900/20 = 45 it will take approximately 45 days to use all the oil in the tank
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Answered by Henry T. • Maths tutor
3190 Views