Which of the following about dalton's theory of matter is true?
a.) atoms can be created
b.) atoms of the same element have the same mass
c.) compounds formed from two elements will not always have the same proportions
d.) atoms cannot be divided into smaller parts

An unknown substance is a white solid at room temperature and has a melting point of 78 °c. which of the following substances is most likely to be the identity of the unknown sample? a. naphthalene, a molecular solid with the formula c10h8 b. silica, a network solid held together by covalent bonds with the formula sio2 c. calcium chloride, an ionic compound with the formula cacl2 d. water, an molecular compound with the formula h2o