Final answer:
Two copper pennies with a mass of 6.64g contain approximately 0.1045 moles of copper, calculated by dividing their combined mass by copper's molar mass of 63.54 g/mol.
Step-by-step explanation:
To determine the number of moles of copper in two copper pennies with a mass of 6.64g, you would use the atomic mass of copper from the periodic table, which is 63.546 amu (or approximately 63.54 g/mol for practical calculations). According to Avogadro's number, one mole of any substance contains 6.022 × 1023 atoms of that substance.
Firstly, you calculate the number of moles using the formula:
moles = mass / molar mass
For copper: moles = 6.64g / 63.54 g/mol
This calculation yields: moles = 0.1045 mol of Cu
Therefore, the two copper pennies have approximately 0.1045 moles of copper.