You measure out 1.8 mL of an aqueous ethylenediamine (H2NCH2CH2NH2) solution. This aqueous solution has a density of 0.950 g/mL and is 25.0% by mass ethylenediamine. How many moles of ethylenediamine are in the 1.8 mL?

7.11x10⁻³ moles ethylenediamine

Explanation:

To find the answer we need to convert the volume to mass using density, the mass to mass of ethylenediamine using the concentration of the solu and to moles using its molar mass (Molar mass ethylendiamine: 60.1g/mol):

Mass:

1.8mL * (0.950g/mL) = 1.71g

Mass ethylenediamine:

1.71g * 25.0% = 0.4275g ethylenediamine.

Moles:

0.4275g * (1mol / 60.1g) =

answer:

the answer is 6 valence electrons.

explanation:

valence is the # of electrons on the outer most shell of an atom.

oxygen has 6.

although, the valency of oxygen is 2, because it only needs to make 2 covalent bonds, or gain 2 electrons, to achieve the stable octet configuration of a noble gas.

that's it!

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~ trueboss72