What is the total mass of oxygen contained in 8.20g of benzoic acid (c6h5cooh)

Mass of oxygen = 2.2 g

Explanation:

Given data:

Mass of benzoic acid= 8.20 g

Mass of oxygen= ?

Solution:

Molar mass of oxygen = 16×2 g/mol

Molar mass of C₆H₅COOH = 7×12 + 1×6 + 2×16

Molar mass of C₆H₅COOH = 84 + 6 + 32

Molar mass of C₆H₅COOH = 122g/mol

Mass of oxygen in 8.20 g of C₆H₅COOH :

Mass of oxygen = 32 g.mol⁻¹/122 g.mol⁻¹ × 8.20 g

Mass of oxygen = 2.2g

"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"

the answer to this question is 3.