# Finding the number of electrons in a given substance

## Homework Statement

I was given this problem in class and I am unable to figure it out:

A copper wire 90.0 cm long and 1.00 mm in diameter has a mass of 6.35 grams.

(a) find the number of electrons in the wire ( Copper has an atomic number of 29; that is there are 29 protons in the copper atom. Copper has an atomic mass of 63.5)

(b) There is one free electron per atom in copper. Find the number of free electrons in the wire.

Me= 9.11e-31

## The Attempt at a Solution

.00635 kg = mass of the wire

(.00635kg) ( 9.11e-31 kg)= 5.8e-33 kg

I really do not know what to do...
K.

## Homework Statement

I was given this problem in class and I am unable to figure it out:

A copper wire 90.0 cm long and 1.00 mm in diameter has a mass of 6.35 grams.

(a) find the number of electrons in the wire ( Copper has an atomic number of 29; that is there are 29 protons in the copper atom. Copper has an atomic mass of 63.5)

(b) There is one free electron per atom in copper. Find the number of free electrons in the wire.

Me= 9.11e-31

## The Attempt at a Solution

.00635 kg = mass of the wire

(.00635kg) ( 9.11e-31 kg)= 5.8e-33 kg

I really do not know what to do...