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Solve the simultaneous equations (1) x + 3y = 7 and (2) 2x + y = 4

It's impossible to solve an equation with two unknowns (x and y) so we must find a way to get rid of either x or y before solving an equation. Using substitution rearrange the equation 1 so x is the only ter...
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Answered by Simon S. • Maths tutor
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(i) What property does Magnesium Oxide have that makes it useful to create heat-resistant bricks to line furnaces? (ii) Explain why H2S exists as a gas and H2O exists as a liquid (at r.t.p).

(i) Magnesium oxide is an ionic compound meaning the elements reside in a lattice held together by very strong electrostatic forces of attraction between their oppositely charged ions. Since bonds are broken...
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Answered by Shahaab N. • Chemistry tutor
17917 Views

How can we calculate product yield using reactants and reaction stoichiometry?

If we know the chemistry for a reaction we only need to know quantities from one of our reactants to calculate a product yield. For instance, in a reaction to make hydrogen peroxide, we can calculate the mas...
JP
Answered by Joshua P. • Chemistry tutor
3153 Views

Why don't Hydrocarbons and Water Molecules mix, and why might an emulsifier fix this?

Hydrocarbons are long chained, non-polar molecules of Carbon and Hydrogen. As the chain length increases the boiling point of oil increases and the intermolecular forces get stronger. At smaller chain length...
JP
Answered by Joshua P. • Chemistry tutor
7919 Views

64% of an audience are female. Work out the ratio females : males Give your answer in its simplest form.

64% are female. This 64% out of 100%. 36% are male So the ratio is 64 : 36 or 32 : 18 Can then be simplified to 16 : 9
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Answered by Jordan Q. • Maths tutor
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