Question

1) List two chemical properties of magnesium metal.

2) List two physical properties of magnesium metal.

3) When 4g of zinc reacts with 1g of oxygen, what mass of zinc oxide is produced? ​

Answer 1

Answer:

(1) Chemical properties of magnesium - Health effects of magnesium - Environmental effects of magnesium

(2) Magnesium is silvery white and very light

(3) 5g ( 4+1 ) of zinc oxide.

Answer 2

Answer:

1) Chemical properties of magnesium metal

• Flammability: Burns in the air with a bright white light
• Oxidation: Combines with oxygen at room temperature to form a thin skin of magnesium oxide

2)  Physical properties of magnesium metal

• Low density
• Good corrosion resistance
• Reasonably strong metal

3)The mass of zinc oxide produced = 4.96 g ≈ 5 g

Explanation:

3) Chemical reaction between zinc and oxygen

   2 Zn  +  $O_{2}$  →  2 ZnO

The number of moles of zinc = $\frac{4}{2*65.38}$ = 0.0305 moles

The number of moles of oxygen = $\frac{1}{32}$ = 0.0312 moles

∴The limiting reagent is zinc

so we can say that the number of moles of zinc and zinc oxide is the same

Therefore the mass of zinc oxide = 0.0305 × mass of zinc oxide

                                                        = 0.0305 × (2 ×81.38)

                                                        = 4.96 g ≈ 5 g