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Empirical Formula of a Hydride

1. The phosphine that is produced by the reaction of water on calcium phosphide contains an impurity, another gaseous hydride of phosphorus, this hydryde contains 94% phosphorus and 6% hydrogen by mass. Calculate the emphirical formula using the percentages.

2. At 136.5C and a pressure of 760 mmHg, 0.22g of the hydride occupies a volume of 111cubic cm.
a. Calculate the volume that the sample would have at STP, assuming that it remains gaseous.
b. Calculate the density of the gaseous hydride of phosphurous at STP in g/litre.
c. Determine the molecular formula of the hydride of phosphorus.

Solution Preview

1. Calculation of empirical formula from percentages requires some idea of the components that make up the compound and the percentage composition of each component. As we are working in percentages, it is best to assume a compound mass of 100g to get a direct mass of each component.

94% of 100 g is 94 grams and that is Phoshorous
6% of 100 grams is 6 grams and that is Hydrogen

The empirical formula is the ratio of moles of ...

Solution Summary

This solution provides explanation and calculations. 325 words.