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Use the following data to explain why NaCl is soluble in water: ∆H = +31 kJmol-1, S(Na+(aq)) = 320.9 JK-1mol-1, S(Cl-(aq)) = 56.5 JK-1mol-1, S(NaCl(s)) = 72.1 JK-1mol-1 Are there any temperatures at which you would not expect NaCl to dissolve?

This is a nice simple calculation question which explores some basic thermodynamic principles and begins to apply them to simple reactions (in this case, solid salt dissolving in water) allowing predictio...

Answered by Kieran R. • Chemistry tutor

7715 Views

How can one differentiate between the organic compounds propanal (CH3CH2CHO) and propanone (CH3COCH3)?

React a sample of each compound with Tollens reagent. The aldehyde (propanal) will be oxidised to a carboxylic acid (propanooic acid) and will form a silver mirror. No change will be observed with the ket...

Answered by Julie T. • Chemistry tutor

4091 Views

What are the necessary conditions for a random variable to have a binomial distribution?

There can only be two possible outcomes, 'success' and 'fail' (e.g heads or tails) There is a fixed number of trialsThe probabilities of 'success' and 'fail' are constant and stay the same in each trial (...

Answered by Julie T. • Maths tutor

2702 Views

How can I write a Personal Statement fit for Oxbridge?

Writing a Personal Statement when applying to Oxford or Cambridge is a different process to any other Personal Statement, particularly for an Arts degree. I teach my students the process of writing the pe...

Answered by • Personal Statements tutor

1905 Views

Solve the quadratic equation x^2 + x - 6 = 0

There are 3 methods for solving quadratic equations;FactorisingThe quadratic equationCompleting the SquareUsing method 1,We observe that 2 and 3 are factors of 6 and that 3 - 2 = 1 so by factoring out we ...

Answered by Thomas A. • Maths tutor

3190 Views