PLEASE HELP ASAP During an investigation, a scientist heated 123.6 g of copper carbonate till it decomposed to form a black residue. The total mass of the black residue formed was 79.6 g. Does the law of conservation of mass hold true in this case? Use complete sentences to justify your answer based on numerical calculations.

Sawyer is studying diffraction. he draws a diagram of a plane wave to show how light waves travel. which best describes sawyer’s error? the wave fronts should be perpendicular to the direction in which the waves move. the arrow showing the direction of movement of the waves should be pointing to the left. the arrow showing the direction of movement of the waves should be pointing downward. the wave fronts should be both parallel and perpendicular to the direction in which the waves move.