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Chemistry

GCSE

Why are metals good conductors of electricity?

Because metals contain a ‘sea’ of delocalised electrons that are free to move around the metallic lattice, carrying charge.

Answered by Aoife M. • Chemistry tutor

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State what is meant by the term covalent bond

Atoms that share electrons due to the electrostatic attraction between the negatively charged pair of electrons and positively charged nuclei.

Answered by Oliver E. • Chemistry tutor

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What is the general formula for Hydrocarbons?

Hydrocarbons have Hydrogen-Carbon bonds and carbon-carbon bonds. The formula is H_nC_2n+2This is made clear when diagrams are drawn from different hydrocarbons and you can deduce this ...

Answered by • Chemistry tutor

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Zinc reacts with sulphuric acid (Zn + H2SO4 --> ZnSO4 + H2). Write out two separate equations for the species that are oxidised and reduced.

Zn --> Zn^2+ + 2e- (OXIDATION) H2^2- + 2e- --> H2 (REDUCTION)

Answered by Sonali V. • Chemistry tutor

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A student wanted to make 10.0 g of zinc chloride. The equation for the reaction is: ZnO(aq) + 2HCl(aq) → ZnCl2(aq) + H2O(l) Calculate the mass of zinc oxide the student needs to react with the dilute acid to make 10.0 g of zinc chloride. [4 marks]

What do we know from the question? 1. we know the balanced equation 2. we know the mass of zinc chloride we want to form. using the equation number of moles = mass/Mr we can calculate the number of moles ...

Answered by Arun S. • Chemistry tutor

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