How many moles are in 2.1 x 10^{24} molecules SiO4

3.5 moles

Explanation:

Based on Avogadro's law:

1 mole of any substance has 6.02 x 10^23 molecules

So, 1 mole of SiO4 = 6.02 x 10^23 molecules

Zmoles of SiO4 = 2.1 x 10^{24} molecules

To get the value of Z, cross multiply:

(2.1 x 10^{24} molecules x 1mole) = (6.02 x 10^23 molecules x Z moles)

2.1 x 10^{24} molecules = (6.02 x 10^23 x Z)

Z = (2.1 x 10^{24}) ➗ (6.02 x 10^23)

Z = 3.5 moles

Thus, there are 3.5 moles of SiO4.

the answer is   c.) 1575 j.

explanation: