Silver sulfide and hydrogen gas are combined to form silver and hydrogen sulfide. 3.0 g of H2 and 100 g of Ag2S are used to produce only 85 g of Ag. a) Write the balanced chemical equation for this reaction.

b) What is the actual yield?

c) Which substance is in excess?

d) What quantity is in excess?

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. 

Isec i will do it and them i will let you know

Combustion is the act or process of burning. therefore, i believe the answer is  a: burning wood.