Question

how many protons are in 891mg of aluminum sulfate?

Answer 1

Mass of Aluminium sulfate = 891 mg = 0.891 g

Molar mass of Al_{2​​​​​​​}(SO​​​​​​​₄)₃ = [(2 × atomic mass of Al) + (3 × atomic mass of S) + (12 × atomic mass of O)] = [( 2 × 27) + (3 × 32) + (12 × 16)] = 54 + 96 + 192 = 342 g/mol

Number of moles of aluminum sulfate = mass / molar mass = 0.891/342 = 2.605 × 10^-3

Now,

​​​​​​Number of moles of aluminium sulfate = Number of protons/ 6.022 × 10²³

2.605 × 10^-3 = Number of protons / 6.022 × 10²³

On solving , we get,

^{​​​​​​}Number of protons = 1.569 × 10²¹

Hence, the number of protons in 891mg of aluminium sulfate is = 1.569 × 10²¹ protons.....

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