Chapter 6, Problem 31A

Interpretation Introduction

Interpretation :

The experimental evidence about a new compound that must be known before its formula must be explained.

Concept Introduction :

Empirical formula of a molecule is the smallest unit which is repeated in the molecule.

Molecular formula of a compound is the representation of the molecule with the number of different atoms present in the molecule.

Answer to Problem 31A

To determine the formula of a new compound the amount of different atoms present in the compound must be known or its empirical formula must be known.

Explanation of Solution

If quantitative estimation of a new compound is done after the qualitative estimation then what are the different elements present in the compound will be known along with the percentages of those elements. From this mole ratio of all the constituent elements and smallest mole ratio will be known. This will give empirical formula. Then molecular formula can be found from the empirical formula using the following relationship.

Molecular formula $\text{=empirical formula×n}$ where n is any positive integer like 1, 2, 3 and so on.

Conclusion

To determine the formula of a new compound the percentage composition of all the constituent elements and molecular weight or vapor density must be known.