A bottle of H3PO4 contains 30.00 g, how many moles are in this container?

Moles in the container : 0.306

Further explanation

Given

30 g of H3PO4

Required

moles in container

Solution

A mole is a unit of many particles (atoms, molecules, ions) where 1 mole is the number of particles contained in a substance that is the same amount as many atoms in 12 gr C-12  

1 mole = 6.02.10²³ particles  

While the number of moles can also be obtained by dividing the mass (in grams) with the molar mass of element or molecule  

MW of H3PO4 = 3.1 + 31 + 4.16 = 98 g/mol

mol = mass : MW

mol = 30 : 98

mol = 0.306

Which metal is less dense

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.