Leigh is preparing popcorn for her friends. She removes a stick of butter from the refrigerator and cuts a fourth of it from the rest. Leigh remembers her lesson in school today about the conservation of mass that occurs during state changes. She wants to test what she learned, so she measures the mass of the butter she will melt. Its mass is 35 g. Then, she places the butter in the microwave and melts it. What should the mass of the liquid butter be once it is melted?

35 since melting will change all the solid butter into liquid butter so the number of atoms inside the liquid butter will be the same as the number of atoms that were present in the solid butter . This means that the mass will not change just as the law of conservation of mass predicted. However , the mass will decrease ( in other words : become less than 35) if he stated that the solid butter has evaporated since we can’t measure the amount of butter that has evaporated ( can not measure gases) . However, due to the law of conservation of mass , we can predict the amount of butter that has evaporated by subtracting the mass of the butter that is still present inside the bowel by the initial mass of the solid butter we used at the beginning of the experiment.