Question

Oxygen forms a number of compounds with nitrogen, many of which are quite reactive. one such compound is 36.86 % by mass n . calculate the number of grams of oxygen present in a sample of this compound that contains 56.00 grams of n .

Answer 1

Mass percentage is defined as the ratio of mass of the element to the total mass of the compound.

The formula of mass percentage is given by:

Mass percentage = $\frac{mass of the element}{total mass of the compound}\times 100$                  (1)

mass of nitrogen = 56.00 grams

Let x be the total mass of the compound.

Put the given values in formula (1):

$\frac{36.86}{100} =\frac{56.00 g}{x}$

x= $\frac{100}{36.86}\times 56 g$

x=  151.92 g

total mass of the compound = 151.92 g

To calculate the mass of oxygen in grams, subtract the mass of nitrogen from the total mass of the compound.

Mass of oxygen =  151.92 g - 56 .00 g = 95.92 g

Thus, mass of oxygen in grams = 95.92 grams.