Final answer:
The mass of a pure gold coin with 0.145 moles of gold is calculated by multiplying the number of moles by the molar mass of gold, resulting in a mass of 28.56 grams.
Step-by-step explanation:
To find the mass of a pure gold coin containing 0.145 moles of gold, we use the concept of molar mass, which is the mass of one mole of a substance. The molar mass of gold (Au) can be determined from the periodic table and is approximately 196.97 g/mol.
Using the formula for mass calculation:
- Mass (m) = number of moles (n) × molar mass (M)
- m = 0.145 moles × 196.97 g/mol
- m = 28.56 grams (rounded to two decimal places)
Therefore, the mass of the gold coin would be 28.56 grams.