How do you find the number of electrons given a mass fo the object?

[Bwilli]

Homework Statement

(a) Calculate the number of electrons in a small, electrically neutral silver pin that has a mass of 13.0 g. Silver has 47 electrons per atom, and its molar mass is 107.87 g/mole.

Homework Equations

N/A

The Attempt at a Solution

I thought to try using the molar mass given and dividing it by mass of the pin.
107.87g/mole / 13 g = 8.298 1/mole

After this point I didn't know what to do next

 

[voko]

How many atoms are in a mole?

 

[SteamKing]

I think you were trying to find the number of moles of silver in the pin, but you would up with a unit of 1/moles in your calculation.

What does this tell you about how to do the calculation correctly?

 

[Bwilli]

Thanks a lot! I used avogadro's number.

(13g)/(107.87g/mole)*(6.022E23atoms/mole)*(47electrons) = 3.41E24 electrons in the silver pin

 

[Nickie]

.

I would approach this problem by using the Avogadro's number and the atomic mass of silver. Avogadro's number, also known as the Avogadro constant, is a fundamental physical constant that represents the number of particles (atoms or molecules) in one mole of a substance. It is approximately equal to 6.022 x 10^23 particles per mole.

To find the number of electrons in the silver pin, we first need to determine the number of silver atoms present in the pin. This can be done by dividing the mass of the pin (13.0 g) by the molar mass of silver (107.87 g/mol). This gives us 0.1205 moles of silver atoms in the pin.

Next, we can use the fact that silver has 47 electrons per atom to calculate the total number of electrons in the pin.

Number of electrons = 0.1205 moles x 6.022 x 10^23 electrons/mole x 47 electrons/atom
= 3.223 x 10^23 electrons

Therefore, there are approximately 3.223 x 10^23 electrons in the silver pin.