Density=mass/volume
density=330/20
density=16.5g/ml
<span>Avogadro's number
represents the number of units in one mole of any substance. This has the value
of 6.022 x 10^23 units / mole. This number can be used to convert the number of
atoms or molecules into number of moles. We calculate as follows:
</span>2.0*10^18 molecules of water ( 1 mol / 6.022 x 10^23 molecules ) = 3.32x10^-6 mol water
Density for Cu: 8.96
g/ml <span>
Density for Ag: 10.5g/ml</span>
First set up an
equation: mass = density * volume <span>
8.96 * x + 10.5* (10.12 - x) = 105.0
The density of the Cu (8.96) times x (the amount of copper)
added to the density of Ag (10.5) times voume of silver (10.12 - the amount of
copper) should equal the total weight.
</span>
Solving for x:<span>
x = 0.818 mL
So
mass of copper = 8.96 * .818 = 7.33
<span>mass percent of copper = 7.33/105 * 100% = 6.98%</span></span>