I ORDER TORECEVE PULL CREBIT YOUMUST SHOW ALL WOR, CORRECT SIGNIFICANT FIGURES A
ID: 587991 • Letter: I
Question
I ORDER TORECEVE PULL CREBIT YOUMUST SHOW ALL WOR, CORRECT SIGNIFICANT FIGURES AND UNITS NAME: 13. Combustion analysis is used to determine the empirical formula of unknown hydrocarbons. In combustion analysis the unknown compound undergoes combustion (burning) in the presence of pure oxygen. When the sample is burned, all of the carbon in the sample is converted to carbon dioxide and all of the hydrogen is converted to water. The carbon dioxide and the water are weighed and with these masses and molar relationships between moles in their formulas for carbon dioxide and water, determine the amount of carbon and hydrogen in the original sample. The amount of any other element can be determined by subtracting the sum of the masses of C and H from the o sample of a compound containing only carbon, hydrogen and oxygen produces 2.445g CO2 and 0.6003g of H20Explanation / Answer
Lets say we have reaction:
A + O2 -----> CO2 + H2O
A is unknown sample of mass 0.8233 g
moles of CO2 = moles of C in sample
2 x moles of H2O = moles of H in sample
moles of O in H2O + CO2 = moles of O in O2 + moles of O in sample
moles of CO2 = mass /molar mass = 2.445 g / 44.01g/mol = 0.05555555 mol
moles of H2O = 0.6003g / 18.01528 g/mol = 0.033322 mol
mass of oxygen = mass of sample -(mass of carbon + mass of hydrogen)
mass of carbon = moles x molar mass of C atom
mass of hydrogen atom = moles x molar mass of h atom
mass of oxygen = 0.8233 g - (0.033322 mol x 2 x 1.008g/mol + 0.055555 mol x 12.0107g/mol)
= 0.088864 g
moles of oxygen = 0.88864g / 15.9997 g/mol = 0.00555 moles
moles of H is 2 x H2O moles = 0.033322 x 2 moles = 0.066644 moles
moles of C = 0.05555 moles
moles of oxygen = 0.0055555 moles
To get empirical formula ,we have to divide by the least no. among these , which is oxygen moles = 0.005555 moles
O = 0.0055555 /0.0055555 = 1
C = 0.05555555/0.00555555 = 10
H = 0.0333222/0.005555555 = 6
empirical formula
C10H6O
I have rectified the mistake sorry for incovenience
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