How many of C8H8's electrons has it gained/lost?

[mono_ten]

Homework Statement

Assume the formula for styrofoam (a polymer containing carbon and hydrogen) is C8H8. In a .25g styrofoam peanut, how many electrons and protons are present if it carries no excess charges? How many Coulumb's of + and - charge does this stand for? How many of the peanut's electrons has been gained/lost if the peanut has an excess charge of +0.10 C?

Homework Equations

The Attempt at a Solution

Well, if this is a typical chemistry problem, in the beginning... I would convert grams to molecules using Avogadro's number.
Not sure how to find the number of protons and electrons after that though. Doesn't it have to do with the atomic number?
After that, I'm not exactly sure how to find Coulumb's of the + and - charges.

 

[Stovebolt]

The Attempt at a Solution

Well, if this is a typical chemistry problem, in the beginning... I would convert grams to molecules using Avogadro's number.

Good start.

Not sure how to find the number of protons and electrons after that though. Doesn't it have to do with the atomic number?

The number of protons in a single atom of a given element is equal to the atomic number. If the sample contains no excess charges, you should be able to find the number of electrons based on the number of protons.

After that, I'm not exactly sure how to find Coulumb's of the + and - charges.

An elementary charge (the charge of one proton (+) or electron (-)) is equal to 1.602 × 10^–19 Coulombs.

 

[thomate1]

I would approach this problem by first identifying the number of atoms present in a .25g styrofoam peanut. Using the molar mass of C8H8, which is 104 g/mol, we can calculate that there are approximately 0.0024 moles of C8H8 in a .25g sample.

Next, I would use the periodic table to determine the number of electrons and protons in each atom of C8H8. Carbon has 6 protons and 6 electrons, while hydrogen has 1 proton and 1 electron. This means that in a .25g styrofoam peanut, there are approximately 0.0024 moles of carbon and 0.0024 moles of hydrogen, which translates to 1.44 x 10^22 carbon atoms and 2.88 x 10^22 hydrogen atoms.

Assuming the styrofoam peanut carries no excess charges, the number of electrons and protons would be equal. This means that there are 1.44 x 10^22 protons and 1.44 x 10^22 electrons in the peanut.

To find the amount of charge, we can use the equation Q = n x e, where Q is the charge in Coulombs, n is the number of electrons, and e is the elementary charge (1.602 x 10^-19 C). Plugging in the numbers, we get:

Q = (1.44 x 10^22)(1.602 x 10^-19) = 2.306 x 10^3 C

This means that there are 2.306 x 10^3 Coulombs of both positive and negative charge in the peanut.

Finally, if the peanut has an excess charge of +0.10 C, we can calculate the number of electrons gained/lost by using the same equation and solving for n:

n = Q/e = (0.10)/(1.602 x 10^-19) = 6.24 x 10^17 electrons

Therefore, the peanut has gained 6.24 x 10^17 electrons to have an excess charge of +0.10 C.