A modern penny weighs 2.5 g but contains only .063 g of copper. How many copper atoms are present in a modern penny? Thanks in advance for any help you can give!
How many mols Cu are in the penny?
That's mols Cu = grams Cu/atomic mass Cu.
Then mols Cu x 6.02E23 = atoms Cu.
2.4x10^24 copper atoms
2.41x10^24
.065 g/1 x 1 mol/106.546 g x(6.022 x 10^24
gives you a total of 3.67 x 10^21 atoms of Cu in .065 g of Cu
To determine the number of copper atoms present in a modern penny, we need to use some basic scientific calculations. Here's a step-by-step explanation of how to calculate it:
1. Find the molar mass of copper:
The molar mass of copper (Cu) is 63.546 grams/mol. This means that one mole of copper atoms weighs 63.546 grams.
2. Convert the mass of copper in the penny to moles:
Given that a modern penny contains 0.063 grams of copper, we divide this value by the molar mass to convert it to moles:
0.063 g ÷ 63.546 g/mol = 0.00099169 mol
3. Convert moles of copper to atoms of copper:
Since 1 mole of any substance contains 6.022 x 10^23 particles (Avogadro's number), we can determine the number of copper atoms by multiplying the number of moles by Avogadro's number:
0.00099169 mol x 6.022 x 10^23 atoms/mol = 5.973 x 10^20 copper atoms
Therefore, there are approximately 5.973 x 10^20 copper atoms present in a modern penny.