25) The Law of conservation of matter tells us that the total number of atoms does not change in a chemical reaction and thus mass is conserved. Select ALL of the reactions that obey the law of conservation of matter
A) 4 NH3 +5 0 -- 4 NO.6H,0
B) 8 H25+ 8 Cl2 - 5; 16 HCI
CH, 20, - CO + H2O
D) HCI + K2CO3 - KCI + H2O + CO2
E) 2 Al(OH)3 + 3 H250- Al2(50)3 + 6H20

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. 

H tricky one let me think and get back to u

Polyethylene is a strong synthetic polymer that can be used to make toys and bottles. this makes plastics which are important also to people but sometimes it lead to harmful environmental effects such as global warming if these plastics are burned.