Chemical Reactions

Which of the following statements concerning 2 moles of ammonia is INCORRECT ?

(Relative atomic masses: C = 12.0, O = 16.0 ; Avogadro constant = 6.02 x 10²³ mol^-1)

• It contains 2 moles of nitrogen atoms.

• It contains 6 x 6.02 x 10²³ hydrogen atoms.

• It contains the same number of atoms as 4 moles of hydrogen chloride.

• It contains the same number of atoms as 44.0 g of carbon dioxide.

Which of the following compounds has the highest percentage by mass of iron ?

(RAM of Fe = 55.8 Formula masses :

iron(II) chloride = 126.8

iron(III) nitrate = 241.8 iron(III) oxide = 159.6)

• Iron(II) chloride

• Iron(III) nitrate

• Iron(III) oxide

The formula of hydrated iron(II) sulphate is FeSO₄ xH₂O. On strong heating, 18.1 g of the hydrated sulphate produces 8.20 g of water. What is the value of x ?

(Formula masses : FeSO₄ = 151.8 H₂O = 18.0)

• 5

• 6

• 7

• 8

When 11.16 g of lead(II) oxide is heated with 0.36 g of carbon powder, lead and carbon dioxide are formed. Which of the following combinations is correct ?

(Relative atomic masses: C = 12.0, O = 16.0, Pb = 207.2)

• Limiting reactant is lead(II) oxide and mass of lead is 10.36 g.

• Limiting reactant is lead(II) oxide and mass of lead is 12.43 g.

• Limiting reactant is carbon and mass of lead is 10.36 g.

• Limiting reactant is carbon and mass of lead is 12.43 g.

Tags

NGSS.HS-PS1-7

Which of the following iron objects is usually prevented from rusting by electroplating ?

• Food can

• Water bucket

• Water tap

• Coat hanger

Tags

NGSS.MS-ETS1-1

Which of the following statements concerning anodization is correct ?

• The strength of the aluminium object is enhanced by anodization.

• The whole aluminium object becomes aluminium oxide after anodization.

• The shape of the aluminium object can be changed by anodization.

• Anodization is a chemical change.

Which of the following statements concerning citric acid is INCORRECT ?

• Citric acid is present in lemons.

• Citric acid is an electrolyte.

• Solid citric acid reacts with magnesium to give hydrogen.

• It aqueous solution contains hydrogen ions.

Which of the following pairs of substances would NOT produce a gas when mixed ?

• Magnesium and ethanoic acid

• Magnesium hydroxide and dilute hydrochloric acid

• Magnesium carbonate and dilute sulphuric acid

• Magnesium and steam

When an aqueous solution of Y is heated with NaOH(aq), an alkaline gas forms. When an aqueous solution of Y is added to acidified AgNO₃(aq), there is no observable change. Which of the following compounds might Y be ?

• KCl

• Ca(NO₃)₂

• NH₄Cl

• NH₄NO₃

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

Which of the following reagents can be used to distinguish between ZnSO₄(aq) and Pb(NO₃)₂(aq) ?(1) NaOH(aq) (2) NH₃(aq) (3) HCl(aq)

• (1) and (2) only

• (1) and (3) only

• (2) and (3) only

• (1), (2) and (3)