Moderate

24g each of carbon and oxygen react to form CO2. The amount of unreacted element left behind is:

Correct answer: B. 15g

  • A. 6g
  • B. 15g
  • C. 16g
  • D. 10g

Explanation

1 mole combines with 1 mole of O2 to give 1 Mole of CO2.No of moles of C in 24 g = 24/12 =2 molesNo of moles of O2 in 24 g = 24/32 = 0.75 molesSince the number of moles of O2 is only 0.75 so it can react with only 0.75 moles of C, and the rest of the C will remain unreacted.Mass of 0.75 moles of C = 12 g/mol x 0.75 mol = 9gUnreacted element left behind = 24-9 =15g

Last updated

About Fundamental Concepts of Chemistry

Mole calculations connect mass, number of particles and Avogadro's number, while balanced equations provide the mole ratios used in stoichiometry. Questions cover limiting and excess reactants, theoretical yield and percentage yield, including identifying which reactant is consumed first and comparing the actual product with the maximum possible product.

Practise Fundamental Concepts of Chemistry

894 free Fundamental Concepts of Chemistry MCQs from Chemistry, each with the correct answer and an explanation. Unlimited attempts, no account needed.

Exams that ask Chemistry questions like this

Chemistry is on 12 papers prepared for on TestUstad, and all of them draw the same bank, so this question is worth knowing for every one of them.

Related questions