Advertisements
Advertisements
Question
The percentage composition of sodium phosphate, as determined by analysis is : 42.1% Na, 18.9% P, 39% of O. Find the empirical formula of the compound.
[H =1, N =14, Na = 23, P = 31, Cl = 35.5, Pt = 195]
Advertisements
Solution
| Element | Atomic mass | Percentage | Relative ratio of moles | Simplest mole ratio | Whole number ratio |
| Na | 23 | 42.1 | 42.1/23 = 1.8 | 1.8/0.6 =3 | 3 |
| P | 31 | 18.9 | 18.9/31 = 0.6 | 0.6/0.6 = 1 |
1 |
| O | 16 | 39 |
39/16 |
2.4/0.6 = 4 | 4 |
Empirical formula = Na3PO4.
APPEARS IN
RELATED QUESTIONS
A compound of X and Y has the empirical formula XY2. Its vapor density is equal to its empirical formula weight. Determine its molecular formula.
If the empirical formula of a compound is CH and it has a vapor density of 13, find the molecular formula of the compound.
A compound made up of two elements X and Y has an empirical formula X2Y. If the atomic weight of X is 10 and that of Y is 5 and the compound ha a vapor density 25, find its molecular formula.
Ethane burns in oxygen to form CO2 and H2O according to the equation:
\[\ce{2C2H6 + 7O2 -> 4CO2 + 6H2O}\]
If 1250 cc of oxygen is burnt with 300 cc of ethane, calculate:
- the volume of CO2 formed.
- the volume of unused O2.
Give the empirical formula of: C6H12O6
A compound of lead has following percentage composition, Pb = 90.66%, O = 9.34%. Calculate empirical formula of a compound. [Pb = 207, O = 16]
Calculate the empirical formula of the compound having 37.6% sodium, 23.1% silicon and 39.3% oxygen.(Answer correct to two decimal places) (O = 16, Na = 23, Si = 28)
The empirical formula of a compound is C2H5. Its vapour density is 29. Determine the relative molecular mass of the compound and hence its molecular formula.
A compound of X and Y has the empirical formula XY2. Its vapour density is equal to its empirical formula weight. Determine its molecular formula.
Silicon (Si = 28) forms a compound with chlorine (Cl = 35.5) in which 5.6 g of silicon combines with 21.3 g of chlorine. Calculate the empirical formula of the compound.
