Engineering Board Exam Reviewer · Chemistry · hard

A compound contains 40% carbon, 6.67% hydrogen and 53.33% oxygen by mass. What is its empirical formula? (Use H = 1, C = 12, N = 14, O = 16, Na = 23, S = 32, Cl = 35.5, Ca = 40)

  1. CHO
  2. C2H4O
  3. CH4O
  4. CH2O

Answer

D. CH2O

Solution

Per 100 g: C = 40/12 = 3.33; H = 6.67/1 = 6.67; O = 53.33/16 = 3.33. Ratio 1 : 2 : 1 CH2O.

More Chemistry questions

  1. What is the percentage by mass of carbon in glucose ( C6H12O6)? (Use H = 1, C = 12, N = 14, O = 16, Na = 23, S = 32, Cl = 35.5, Ca = 40)
  2. What is the percentage of calcium by mass in CaCO₃? (Use H = 1, C = 12, N = 14, O = 16, Na = 23, S = 32, Cl = 35.5, Ca = 40)
  3. What is the percentage by mass of oxygen in water? (Use H = 1, C = 12, N = 14, O = 16, Na = 23, S = 32, Cl = 35.5, Ca = 40)
  4. How many atoms are in 3 mol of helium?
  5. What is the mass of 0.25 mol of sodium hydroxide ( NaOH)? (Use H = 1, C = 12, N = 14, O = 16, Na = 23, S = 32, Cl = 35.5, Ca = 40)
  6. How many molecules are in 44 g of carbon dioxide? (Use H = 1, C = 12, N = 14, O = 16, Na = 23, S = 32, Cl = 35.5, Ca = 40)
  7. How many moles are there in 90 g of water? (Use H = 1, C = 12, N = 14, O = 16, Na = 23, S = 32, Cl = 35.5, Ca = 40)
  8. What is the molar mass of glucose, C6H12O6? (Use H = 1, C = 12, N = 14, O = 16, Na = 23, S = 32, Cl = 35.5, Ca = 40)
  9. What is the molar mass of calcium carbonate, CaCO₃? (Use H = 1, C = 12, N = 14, O = 16, Na = 23, S = 32, Cl = 35.5, Ca = 40)
  10. What is the molar mass of sulfuric acid, H2SO4? (Use H = 1, C = 12, N = 14, O = 16, Na = 23, S = 32, Cl = 35.5, Ca = 40)

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