Chemistry

1The dry Leclanché cell uses

2Doubling the current while keeping the time constant

3Cracking is the process of

4The bond angle in ammonia is about 107° because

5Primary alkanols are oxidised by acidified potassium dichromate(VI) first to

6The splitting of a heavy nucleus into two lighter nuclei is called nuclear ___.

7Antacid tablets relieve indigestion by

810 cm³ of 0.1 mol/dm³ H₂SO₄ neutralised 25.0 cm³ of NaOH. H₂SO₄ + 2NaOH → Na₂SO₄ + 2H₂O. Find the concentration of the NaOH.

9E°(Cu²⁺/Cu) = +0.34 V and E°(Zn²⁺/Zn) = −0.76 V. The e.m.f. of the Zn/Cu cell is ___ V.

10How many molecules are in 0.25 mol of glucose? (L = 6.02 × 10²³)

11Sodium chloride is best prepared from sodium hydroxide and hydrochloric acid by

12Silicon (Z = 14) is in period ___ of the periodic table.

13The standard hydrogen electrode has an electrode potential of

14A reaction that gives out heat to the surroundings is

15Steel is

16The pH of pure water at 25 °C is

17In the extraction of iron, limestone is added to the blast furnace to

18Sulphuric acid has a basicity of ___.

19The molecular formula of a compound with empirical formula CH₂ and molar mass 42 g/mol is

20The process that makes sulphuric acid is the ___ process.