Igcse Model Questions Vol1 2018 Chemistry Question 4

Practice practical question 4 from the 2018 Igcse Model Questions Vol1 Chemistry examination. This question covers Mole Concept .

Igcse Model Questions Vol1 2018 Chemistry Practical
Topic: Mole Concept
Question 4 IGCSE_MODEL_QUESTIONS_VOL1 • 2018 • CHEMISTRY • practical

A 0.500 g sample of a commercial sodium carbonate (Na₂CO₃) preparation is dissolved in 100 cm³ of water. The solution is then acid‑titrated with 0.100 mol dm⁻³ hydrochloric acid (HCl) until the endpoint is reached. The volume of HCl used is recorded as 23.5 cm³. The same sample is also heated in a test tube, and the volume of carbon dioxide gas (CO₂) produced at 25 °C and 1.00 atm is measured as 12.0 cm³.

Question Parts

( a )
Calculate the number of moles of Na₂CO₃ present in the sample based on its mass. (Molar mass of Na₂CO₃ = 106.0 g mol⁻¹)
( b )
From the titration data, determine the number of moles of Na₂CO₃ that reacted with HCl. (Balanced equation: Na₂CO₃ + 2 HCl → 2 NaCl + H₂O + CO₂)
( c )
Using the gas‑collection data, calculate the number of moles of CO₂ produced. (Assume ideal gas behaviour; R = 0.0821 L atm mol⁻¹ K⁻¹, temperature = 298 K.)
( d )
Based on the mass of the sample (a) and the moles of Na₂CO₃ that actually reacted (b), calculate the percent purity of the commercial sample.
( e )
Suggest one probable source of error that could account for the low calculated purity and propose a way to reduce it.

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About This Question

This is Igcse Model Questions Vol1 2018 Chemistry Question 4. It is one of the practical questions from the 2018 Igcse Model Questions Vol1 Chemistry examination.

The question covers Mole Concept .

View More Igcse Model Questions Vol1 2018 Chemistry Questions More Igcse Model Questions Vol1 Practice Questions Back to Questions

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