Use the table of molar masses to answer the question.

Question

Element Molar Mass (g/mol)
silicon 28.09
oxygen 16.00
How many molecules of silicon dioxide (SiO2) are there in a 15-gram sample?

Responses-

a- 1.251×10^23

b- 2.049×10^23

c- 1.503×10^23

d- 6.022×10^23

Answer 1

To solve this problem, we first need to calculate the number of moles of silicon dioxide in the sample:

15 g SiO2 x 1 mol SiO2/60.08 g = 0.249 mol SiO2

Then, we can use Avogadro's number (6.022 x 10^23) to convert from moles to molecules:

0.249 mol SiO2 x 6.022×10^23 molecules/mol = 1.503×10^23 molecules SiO2

Therefore, the answer is (c) 1.503×10^23.