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) =

7.11x10⁻³ moles ethylenediamine

Mass is the amount of matter in an object.  weight is the measurement of the pull of gravity on an object.  say for example, you travel to the moon which has a different gravitational field compared to the gravitational field of earth. (gravitational fields: earth = 1, moon = 0.165)  now when you are on the moon, the pull of gravity on you is different than on the earth. and as weight is the measurement of the pull of gravity on an object, that means yes, your weight can and will change on the moon.  however, on the moon, on earth or even on jupiter, the amount of mass inside of you remains the same. meaning your physical mass remains constant.  in conclusion it is possible for your weight to change as your mass remains constant.