If a particular ore contains 55.4% calcium phosphate, what minimum mass of the ore must be processed to obtain 1.00kg of phosphorus?

First, we require the formula of calcium phosphate. This is:
Ca₃(PO₄)₂

And its mass is 310 g/mol

The atomic mass of phosphorus is 31 g/mol, and as there are 2 moles of P per mole of calcium phosphate, the mass of P is 62 g/ mol calcium phosphate

Now, we calculate the percentage mass of phosphorus in calcium phosphate. This is:
62/310 * 100 = 20%

So, if we need 1 kg of P, we need:

1/20% = 5 kg of calcium phosphate. This means we need:

5 / 55.4% = 9.02 kg of ore

9.02 kg of ore is required.

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.