The kp for the reaction below is 1.49 × 108 at 100.0°c:

co(g) + cl2(g) → cocl2(g)

in an equilibrium mixture of the three gases, pco = pcl2 = 2.22 × 10-4 atm. the partial pressure of the product, phosgene (cocl2), is atm.

The rate constants, K, can be expressed in many different terms. In this case, Kp is the equilibrium constant expressed in terms of gas partial pressure. The formula for this is:
Kp = [P(product C) × P(product D)] / [P(reactant A) × P(reactant B)]
As there is only one product, we will use only its pressure in the numerator. 
Kp = [P(COCl2)] / [P(CO) × P(Cl2)]
P(COCl2) = 1.49 × 10⁸ × 2.22 × 10⁻⁴ × 2.22 × 10⁻⁴
P(COCl2) = 7.34 atm

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.