Question

A copper wire (density = 8.96 g/cm^3) has a diameter of 0.35 mm. If a sample of this copper wire has a mass of 10. g, how long is the wire?

Answer 1

Take HL math.

Answer 2

Okay so you are given density, mass, and the diameter of a copper wire that means that you can relate the information given to volume of the wire and utilize density formula.

Answer 3

D = m/v, Volume = mass/density

Answer 4

Now think of the wire as a cylinder so (pi)(r^2)L

Answer 5

So (pi)(r^2)L = 10g/(8.96g/cm^3)

Answer 6

pi = 3.14....(more precise using this function on your calculator)
r = (diameter)/2 = 0.35/2 = 0.175

Answer 7

So now the only unknown left in your equation is L which represents the length of the wire (or how long the wire is)

Answer 8

Before we proceed you have make sure that your units of length are the same so you can convert the radius 0.175 mm to cm

Answer 9

radius = 0.0175 cm

Answer 10

L = 10g/(8.96g/cm^3)/(0.0175cm)^2/(3.14)
L = 1160.02145cm

Do you follow?

Answer 11

thank you so much! very clear

Answer 12

great! you're welcome