Advertisements
Advertisements
Question
The percentage composition of sodium phosphate as determined by analysis is 42.1% sodium, 18.9% phosphorus and 39% oxygen. Find the empirical formula of the compound.
Advertisements
Solution
| Element | Atomic weight | % age | Relative number of moles | Simplest ratio of atoms |
| Na | 23 | 4.21 | `42.1/23` = 1.83 | `1.83/0.61` = 3 |
| P | 31 | 18.9 | `18.9/31` = 0.61 | `0.61/0.61` = 1 |
| O | 16 | 39 | `39/16` = 2.43 | `2.43/0.61` = 4 |
∴ Empirical formula is Na3PO4.
APPEARS IN
RELATED QUESTIONS
On analysis, a substance was found to contain:
C = 54.54%, H = 9.09%, O = 36.36%
The vapour density of the substance is 44, calculate its empirical formula.
An organic compound, whose vapour density is 45, has the following percentage composition,
H = 2.22%, O = 71.19% and remaining carbon. Calculate its empirical formula.
An organic compound contains H = 4.07%, Cl = 71.65% chlorine and remaining carbon. Its molar mass = 98.96. Find its Empirical formula.
A hydride of nitrogen contains 87.5% percent by mass of nitrogen. Determine the empirical formula of this compound.
Find the empirical formula of a compound containing 17.64% hydrogen and 82.35% of nitrogen.
A compound X consists of 4.8% carbon and 95.2% bromine by mass. Determine the empirical formula of this compound working correctly to one decimal place (C = 12; Br = 80).
An experiment showed that in a lead chloride solution, 6.21 g of lead is combined with 4.26 g of chlorine. What is the empirical formula of this chlorine? (Pb = 207; Cl = 35.5)
The following experiment was performed in order to determine the formula of a hydrocarbon. The hydrocarbon X is purified by fractional distillation.
0.145 g of X was heated with dry copper (II) oxide and 224 cm3 of carbon dioxide was collected at S.T.P.
Calculate the empirical formula of X by the following step:
Calculate the number of moles of carbon dioxide gas.
The following experiment was performed in order to determine the formula of a hydrocarbon. The hydrocarbon X is purified by fractional distillation.
0.145 g of X was heated with dry copper (II) oxide and 224 cm3 of carbon dioxide was collected at S.T.P.
Calculate the empirical formula of X by the following step:
Calculate the mass of hydrogen in sample X.
The following experiment was performed in order to determine the formula of a hydrocarbon. The hydrocarbon X is purified by fractional distillation.
0.145 g of X was heated with dry copper (II) oxide and 224 cm3 of carbon dioxide was collected at S.T.P.
Calculate the empirical formula of X by the following step:
Deduce the ratio of atoms of each element in X (empirical formula).
