A 5 g sample of impure magnesium carbonate is reacted with an excess of hydrochloric acid: MgCO 3 ( s ) + 2 HCl ( aq ) → MgCI 2 ( aq ) + H 2 O ( l ) + CO 2 ( g ) 1250 cm 3 of carbon dioxide is collected at rtp. How many moles of CO 2 are produced?

Since, the volume of carbon dioxide collected is 1250 Cm 3 = 1 . 25 dm 3 . Number of moles of CO 2 = 1 . 25 dm 3 24 dm 3 ≈ 0 . 052 mol

A 5 g sample of impure magnesium carbonate is reacted with an excess of hydrochloric acid: MgCO 3 ( s ) + 2 HCl ( aq ) → MgCI 2 ( aq ) + H 2 O ( l ) + CO 2 ( g ) 1250 cm 3 of carbon dioxide is collected at rtp. How many moles of CO 2 are produced?

Since, the volume of carbon dioxide collected is 1250 Cm 3 = 1 . 25 dm 3 . Number of moles of CO 2 = 1 . 25 dm 3 24 dm 3 ≈ 0 . 052 mol

A 5 g sample of impure magnesium carbonate is reacted with an excess of hydrochloric acid: MgCO 3 ( s ) + 2 HCl ( aq ) → MgCI 2 ( aq ) + H 2 O ( l ) + CO 2 ( g ) 1250 cm 3 of carbon dioxide is collected at rtp. Calculate the % purity of the 5 g sample. A r : C = 12 , O = 16 , Mg = 24

1250 Cm 3 of carbon dioxide contains 0 . 052 mol . MgCO 3 ( s ) + 2 HCl ( aq ) → MgCI 2 ( aq ) + H 2 O ( l ) + CO 2 ( g ) From the reaction, it is clear that one mole of magnesium carbonate gives one mole of carbon dioxide. Hence, 0 . 052 mol or 1250 Cm 3 of carbon dioxide will be collected by 0 . 052 mol of magnesium carbonate. Mass of 0 . 052 mol of magnesium carbonate = 0 . 052 mol × 84 g = 4 . 368 g Percentage purity of magnesium carbonate sample is = 4 . 368 g 5 g × 100 ≈ 87 %

E M B I B E

Complete Chemistry for Cambridge IGCSE® Second Edition>Chapter 6 - Using Moles>Checkup on Chapter 6>Q 14

EASY

Upper Secondary: IGCSE

IMPORTANT

Earn 100

A $5 g$ sample of impure magnesium carbonate is reacted with an excess of hydrochloric acid:

${MgCO}_{3} (s) + 2 HCl (aq) \to {MgCI}_{2} (aq) + H_{2} O (l) + {CO}_{2} (g)$

$1250 {cm}^{3}$ of carbon dioxide is collected at rtp. How many moles of ${CO}_{2}$ are produced?

Important Questions on Using Moles

MEDIUM

Upper Secondary: IGCSE

IMPORTANT

Complete Chemistry for Cambridge IGCSE® Second Edition>Chapter 6 - Using Moles>Checkup on Chapter 6>Q 14

A $5 g$ sample of impure magnesium carbonate is reacted with an excess of hydrochloric acid:

${MgCO}_{3} (s) + 2 HCl (aq) \to {MgCI}_{2} (aq) + H_{2} O (l) + {CO}_{2} (g)$

$1250 {cm}^{3}$ of carbon dioxide is collected at rtp. What mass of pure magnesium carbonate would give this volume of carbon dioxide? $[A_{r} : C = 12, O = 16, Mg = 24]$