Question

Pure liquid hydrogen peroxide (H2O2) has a density of 1.14 gr/cm^3. Determine how many coulombs of positive charge are in one gallon of pure liquid hydrogen peroxide:

Answer 1

Volume V = 1 gallon = 3.78541 x10 ^-3 m ³

Density D = 1.14 g / cm ³

Mass of the liquid hydrogen peroxide M = VD

                                                          = 4.315 x10 ^-3 g

molar mass of hydrogen peroxide M ' = ( 2 x 1 ) + ( 2 x 16 )

                                                      = 34 g / mol

So, Number of moles od liquid hydrogen paroxide n = M / M '

                                                                          = 1.269 x10 ^-4 mol

We know 1 mole contains 6.023 x10 ²³ H2O2 molecules

So, n moles have ( n X 6.023 x10 ²³ H2O2 molecules )

i.e., the liquid contains 7.644 x10 ¹⁹ molecules

Each molecule have two positive charges.

So, 7.644 x10 ¹⁹ molecules have 2 x 7.644 x10 ¹⁹ positive charges

i.e., 1.528 x10 ²⁰ positive charges.

Therefore Total charge of 1.528 x10 ²⁰ positive charges Q = 1.528 x10 ²⁰ x 1.6 x 10 ^-19 C

Since each positive charge have 1.6x10 ^-19 C

So, Q = 24.46 C