Write two examples of
1: physical chemistry (worth 2 points)
2: organic chemistry (worth 2 points)
3: inorganic chemistry (worth 2 points)
4: biochemistry (worth 2 points)
5: industrial chemistry (worth 2 points)
6: nuclear chemistry (worth 2 points)
7: environmental chemistry (worth 2 points)
8: analytical chemistry (worth 2 points)

Physical chemistry :

Nitric acid eating through wood. boiling an egg

Organic chemistry :

soap  detergent

Inorganic chemistry :

sodium chloride (NaCI) (Used as table salt)Silicon dioxide (SiO2) (used in computer chips and solar cells)

Biochemistry :

The human bodymuscles

Industrial chemistry :

Sulfuric Acid (H 2SO4) nitrogen (N2)

Nuclear chemistry :

Element radium decays by emitting a-particles and is converted into another element radon. Carbon-14 is continuously produced in the atmosphere where high energy neutrons from space collide with nitrogen-14.

Environmental chemistry :

coppermercury

Analytical chemistry :

speedcost

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. 

A.(nh4)(2co3)is the correct answer