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Calculate the percentage composition by mass of Lithium Sulfate, Li2SO4.

(Taken from GCSE WJEC Additional Science Book- First Published in 2012) and I have adapted the answer given.Relative atomic masses: Li = 7 ; S= 32 ; O=161) Calculate molecular mass of lithium sulfate (Li2SO4...
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Answered by Elinor L. • Chemistry tutor
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Complete the square and hence sketch the graph of f(x) = x^2 + 2x + 7

Consider (x + 1)^2, where we halved the coefficient of x to obtain 1. This gives us x^2 + 2x + 1, which looks similar to our function, except it differs by a constant value of 6, hence, by adding 6 to (x + 1...
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Answered by Jordan P. • Maths tutor
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What is a tropism

Tropism is directional growthPhototropism is directional growth in response to light.Negative phototropism is growing away from the light e.g. in the rootsPositive phototropism is growing towards the light e...
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Answered by Vikram M. • Biology tutor
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how does speciation occur

A change in the environment occurs. Through random mutations already present in the population (this is known as natural variation) certain individuals will be able to cope with the change more so than other...
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Answered by Vikram M. • Biology tutor
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If I am given a line, how do I find a line that is parallel to it? What about perpendicular?

The key fact here is to remember the relationship between the gradients of lines which are parallel and perpendicular. Two lines that are parallel will always have the same gradient. So if we have a line y =...
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Answered by Harry W. • Maths tutor
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