Revision

What is different about the nucleous of isotopes?

• the same number of protons, but different number of neutrons

• the same number of protons, and the same number of neutrons

• a different number of protons, and a different number of neutrons

• a different number of protons, and the same number of neutrons

Methane, CH4, burns in the air to form carbon dioxide and water. What is the balanced equation for this reaction?

• CH_4(g) + O_2(g) → CO_2(g) + 2H₂O_(g)

• CH_4(g) + 2O_2(g) → CO_2(g) + 2H₂O_(g)

• CH_4(g) + 2O_2(g) → CO_2(g) + H^₂O_(g)

• CH_4(g) + 3O_2(g) → CO_2(g) + 2H₂O_(g)

What is the number of molecules in 500 cm³ of oxygen under standard conditions?

• 3*10²³

• 3*10²⁶

• 1.25*10²¹

• 1.34*10²²

Which of the following definitions is correct for the term atomic mass?

• The mass of an electron

• 1/12 the mass of carbon-12 atom

• the mass of hydrogen-1 atom

• the mass of a proton

Which of the following show the relative formula mass of ammonium sulfate, (NH₄)₂SO₄?

• 98

• 132

• 123

• 231

Which of these is the least reactive element in Group I?

• Cs

• Li

• K

• Na

Which change to an atom occurs when it forms a positive ion?

• It gains electrons.

• It gains protons.

• It loses electrons.

• It loses protons.

Which reaction is endothermic?

• acid neutralising alkali causing a temperature increase

• adding magnesium to hydrochloric acid

• calcium carbonate decomposing when heated

• combustion of fossil fuels

Vanadium is a transition element and forms several oxides. In which of the following reactions does vanadium undergo oxidation?

Which group contains elements that are all unreactive?

• Group 7

• Group 1

• Group 8

• Group 2