A coin dealer offers to sell you an ancient nickel coin that is 3.1 cm in diameter and 4.65 mm in thickness.
A) The density of nickel is 8.9 g/cm3. How much should the coin weigh if it is pure nickel? (in grams)
B) If nickel sells for $0.216 per troy ounce, how much is the nickel content worth? (1 troy ounce = 31.1 g)
My attempt:
Volume=pi(1.55)^2(.465) that's all
your volume equation is correct now multiple through.
remember that density = mass/volume
now arrange the equation to find the mass
So mass is 32.1? grams
For part B what proportion do I have to do?
I think you put your numbers backwards. You should have gotten 31.2 grams
O thanks and how do i start part B. I don't understand
Are sig figs important for this problem?
Yes
Okay for B you simply divide the actual mass of the coin by the grams equivalent to a troy ounce.
31.2 g/31.1 g = 1.00
Luckily they have approximately a 1 to 1 ratio
Multiply 1.00 * $0.216 which is $0.216
With the correct number of sig figs it would be $0.22