empirical formulas

Front

What is an empirical formula?

Back

An empirical formula is the simplest whole-number ratio of atoms of each element in a compound.

Front

How do you calculate the empirical formula from percent composition?

Back

Convert the percentages to grams, then to moles, and divide by the smallest number of moles to find the simplest ratio.

Front

What is the empirical formula for 40.05% S and 59.95% O?

Back

SO3

Front

How do you find the mass of a compound from moles?

Back

Multiply the number of moles by the molar mass of the compound.

Front

What is the molar mass of (NH4)3PO4?

Back

The molar mass is 149.09 g/mol.

Front

What is the mass of 0.75 moles of (NH4)3PO4?

Back

111.75 g

Front

What is the empirical formula for N2S3?

Back

N2S3

Front

How do you determine the percent by mass of an element in a compound?

Back

Divide the mass of the element in one mole of the compound by the molar mass of the compound, then multiply by 100.

Front

What is the percent by mass of sodium in NaCl?

Back

39%.

Front

What is the molecular formula for glycerol with a molar mass of 92.09 g/mol?

Back

C3H8O3.