Gold has a molar (atomic) mass of \(197 \mathrm{~g} / \mathrm{mol}\). Consider a 2.56\(g\) sample of pure gold vapor. (a) Calculate the number of moles of gold present. (b) How many atoms of gold are present?

Short Answer

Expert verified
The number of moles is \(0.013\) and the number of atoms is \(7.81 \times 10^{21}\)

Step by step solution

01

Calculation of number of moles

The number of moles of a substance is given by the formula: \[ number of moles = \frac{mass of substance}{molar mass of substance}\] For gold, this becomes \[number of moles = \frac {2.56 g}{197 g/mol} \]
02

Evaluation of the number of moles

Calculate the value on the right hand side of the equation to get the number of moles.
03

Calculation of number of atoms

The number of atoms in a substance is given by the formula: \[ number of atoms = number of moles \times Avogadro's number\] Substituting the values, we get \[ number of atoms = number of moles \times 6.022 \times 10^{23} \]
04

Evaluation of the number of atoms

Calculate the value on the right hand side of the equation to get the number of atoms.

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