Question

How many oxygen atoms are there in 582 grams of caffeine (CH10N402, 194 g/mol)? Avogadro's Number: 1 mole = 6.02 x 1023 species A. 2 B. 6 C. 1.81 x 1024 D. 3.61 x 1024 F None of the above

Answer 1

Answer:

3.61 * 10 ²⁴atoms.

Explanation:

Moles is denoted by given mass divided by the molecular mass ,

Hence ,

n = w / m

n = moles ,

w = given mass ,

m = molecular mass .

From the question ,

w = 582 g

m = 194 g/mol

The number of moles can be calculated from the above formula , and substituting the respective values ,

n = w / m  = 582 g / 194 g/mol  =  3 mol

In the molecular formula of caffeine ,

In 1 mole of caffeine their are - 2 moles of Oxygen.

Therefore , in  3 moles of Caffeine there will be 6 moles of oxygen.

As well know ,

one mole of any substance contains 6.023*10²³ atoms,

Therefore , in  6 mol of oxygen =  6 * 6.023*10²³ atoms  = 3.61 * 10 ²⁴atoms.