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3.1 Introducing chemical reactions

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Question 2
F

Water has the formula H2O\mathrm{H_{2}O}H2​O.

Use the Periodic Table. Selenium, Se, is in the same group as oxygen.

What is the formula of the compound formed when hydrogen reacts with selenium?

[1]
A

HSe\mathrm{HSe}HSe

B

H3Se\mathrm{H_{3}Se}H3​Se

C

H6Se\mathrm{H_{6}Se}H6​Se

D

H2Se\mathrm{H_{2}Se}H2​Se

Markscheme

3.1 Introducing chemical reactions Questions

  1. GCSE
  2. /Chemistry
  3. /3.1 Introducing chemical reactions

55 exam-style questions on OCR GCSE Chemistry 3.1 Introducing chemical reactions, covering 3.1.1 Writing formulae and balanced chemical equations, 3.1.2 Formulae of compounds from ions, and state symbols, 3.1.3 Conservation of mass and observed changes in mass, 3.1.4 Half equations and balanced ionic equations, 3.1.5 The mole and the Avogadro constant, and 3.1.6 Stoichiometry, limiting reactants and reacting masses. Each one has a worked solution and a mark scheme showing where the marks go.

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