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Why do ionisation energies typically increase upon going across a period yet decrease upon going down a group?

‘Ionisation energy’ is the term used to describe the amount of energy it takes to remove an electron from an atom to form a positively charged ion. It is usually represented by the unit kJ/mol, meaning it...

Answered by Lewis M. • Chemistry tutor

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Express square root of 48 in the form n x square root of 3 , where n is an integer

We know that 3 x 16 = 48 This is equivalent to saying 3 x 4^2 = 48 Therefore the square root of 48 can be written as square root of (4^2 x 3) = 4 x square root 3

Answered by Helena W. • Maths tutor

9741 Views

A curve has equation y=x^2 + (3k - 4)x + 13 and a line has equation y = 2x + k, where k is constant. Show that the x-coordinate of any point of intersection of the line and curve satisfies the equation: x^2 + 3(k - 2)x + 13 - k = 0

When we deal with points of interception, this immediately indicates that these two equations have to equal. Therefore, begin by equaling these two equations: x^2 + (3k - 4)x + 13 = 2x + k Bring all figur...

Answered by Helena W. • Maths tutor

12440 Views

What is the difference between using als and wenn?

Als is used for a sentence that is in the past, for example 'als ich jünger war...' when I was younger. Wenn is used to mean 'if or when' and often has a conditional sense, for example 'wenn ich mehr Geld...

Answered by Jennifer F. • German tutor

24777 Views

When would I use the subjunctive?

You would use the subjunctive mood when you wish to express a personal opinion or a statement that has an element of doubt. Certain phrases can trigger the subjunctive case and these can simply be learnt ...

Answered by Jennifer F. • French tutor

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