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.

hloride, what is the mass of calcium in

explanation:

"you start with 15.67 g mgco3-xh2o, when heated and all the water is removed, you are left with 7.58 g mgco3 only.

therefore, you had 15.67 - 7.58 = 8.09g h2o  

moles of each :

7.58g mgco3 = ? moles = 7.58g / 83.4g/mole = 0.09moles  

8 09g h2o = ? moles = 8.09g / 18g/mole = 0.44moles  

molar ratio between the two by dividing both numbers by the smallest number :

0.09 / 0.09 = 1  

0.44 / 0.09 = 4.8  

mgco3-5h2o"