A5.0-gram sample of fe(s) is to be placed in 100. milliliters of hcl(aq). which changes will result in the fastest rate of reaction? 1. increasing the surface area of fe(s) and increasing the concentration of hcl(aq) 2. increasing the surface area of fe(s) and decreasing the concentration of hcl(aq) 3. decreasing the surface area of fe(s) and increasing the concentration of hcl(aq) 4. decreasing the surface area of fe(s) and decreasing the concentration of hcl(aq)

The answer is increasing the surface area of Fe(s) and increasing the concentration of HCl(aq). 

the rate of reaction can be increased if the interaction between the reactants in better. by increasing the surface area of a solid, such as Fe, you make more possible each molecule of Fe to interact with HCl. Also, by increasing the concentration of HCl, it mean there is more molecule of HCl to interact with Fe.

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.