Chemistry 9 Gen - Term 3 Review

In Stoichiometry, the ratio of moles is equal with the ratio of ...

• volumes

• coefficients

• masses

• concentrations

Which statement is correct about Stoichiometry?

• Ratio of moles is the same with ratio of volumes.

• At the same pressure and temperature, gases with the same coefficients will have equal volume.

• The moles of all substances in the same chemical reaction are always the same.

• Ratio of moles is the same with ratio of masses.

4 Li + O₂ → 2Li₂O

The ratio of moles between Li and O₂ is ...

• 2 : 1

• 1 : 2

• 1 : 4

• 4 : 1

Use the information below to answer questions No. 4, 5 and 6. 

150 cm³ of hydrochloric acid 0.2 mol/dm³ is used to neutralise 200 cm³ of magnesium hydroxide as shown in the reaction below. 

Mg(OH)₂(aq) + 2 HCl(aq) → MgCl₂(aq) + 2 H₂O(l).

What is the moles of hydrochloric acid?

• 0.0300 moles

• 0.750 moles

• 30.0 moles

• 750. moles

Use the information below to answer questions No. 4, 5 and 6. 

150 cm³ of hydrochloric acid 0.2 mol/dm³ is used to neutralise 200 cm³ of magnesium hydroxide as shown in the reaction below. 

Mg(OH)₂(aq) + 2 HCl(aq) → MgCl₂(aq) + 2 H₂O(l).

What is the mole ratio between hydrochloric acid and magnesium hydroxide?

• 2 : 1

• 1 : 2

• 1 : 1

• 2 : 2

Use the information below to answer questions No. 4, 5 and 6. 

150 cm³ of hydrochloric acid 0.2 mol/dm³ is used to neutralise 200 cm³ of magnesium hydroxide as shown in the reaction below. 

Mg(OH)₂(aq) + 2 HCl(aq) → MgCl₂(aq) + 2 H₂O(l).

What is the concentration of magnesium hydroxide solution?

• 0.100 mol / dm³

• 0.150 mol / dm³

• 0.0750 mol / dm³

• 0.0250 mol / dm³

Fe₂O₃(s) → Fe(s) + O₂(g)     [NOT BALANCED]

What is the mass of iron produced when 20 g of iron(III) oxide is decomposed?

[Ar Fe = 56 ; O = 16]

In titration, solution with unknown concentration in the conical flask is called ...

• Titrant

• Analyte

• Burette

• End point

Which are the main chemical(s) that should be present in titration?

You can choose more than one answer.

• Titrant

• Analyte

• pH indicator

• Sodium hydroxide

To keep the accuracy of our experiment, we need to redo the titration at least ... times.