Aurelia dropped a piece of metal into a beaker, and then she added acid to it. She saw colorless bubbles rising from the metal. The metal began to turn black. What type of change did Aurelia see?

Chemical change

Explanation:

From all indicators, Aurelia is seeing a chemical change occurring in the reaction here.

A chemical change is a change in which new substances are produced. For every chemical change:

they are not easily reversiblethey lead to production of new kinds of substancesinvolves mass changerequire considerable amount of energy.

We start off and end with:

         Metal   +     Acid →     Black metal     +    rising gaseous bubbles

Clearly, it is shown that new products are formed and this reaction is impossible to reverse in order to get the reactants back.

This is a typical chemical change.

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. 

Ithink is a because if say increased in electronegativity