** *im so stuck on this test i dont understand any of it* which statement is a correct statement for the law of conservation of mass? a. the total mass decreases during a chemical reaction b. the total mass increases in a chemical reaction c. the total mass remains the same during a chemical reaction d. the total mass is unpredictable in a chemical reaction which element(s) are not balanced in this equation? fe2o3+3 co -> fe+3 co2 a. only the o is unbalanced b. c and o are bothe unbalanced c. fe and o are both unbalanced d. only the fe is unbalanced

Remember that mass changes only occur because a gas is being released into the atmosphere or because a gas from the atmosphere is being used as a reactant -no atoms are created or destroyed only rearranged :-)

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.