Answer :
The mass in grams of carbon that contains as many molecules as 21g of krypton is 3 grams.
What is molecular mass?
An element's molecular mass is defined as the total of the masses of a elements that make up the molecule. A atomic mass of an element is multiplied by the number of atoms present in the molecule, and then the masses of all of the elements in the molecule are added.
The molecular mass of carbon is 12 g/mol.
The molecular mass of krypton is 84 g/mol.
Now according to the question;
To begin, we must determine the number of moles in 21 g of Krypton by dividing the above mass by the molar mass of Krypton.
n = m/μ
m is the mass of carbon = 21 g.
μ is the molecular mass of the krypton = 84 g/mol.
Substitute the values;
n = 21/84
n = 0.25 mol.
Now, calculate the mass of (0.25 mol) of carbon, which we can do by simply multiplying the number of moles by the molar mass of carbon;
m = n×μ
n = number of moles = 0.25 mol
μ = molecular mass of carbon = 12 g/mol
m = 0.25×12
m = 3 g.
Therefore, the mass of the carbon is evaluated as 3 g.
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