A piece of metal has density of 11.3g/cm and volume of 6.7cm
What is the mass of this
Piece of melal?

The mass should be 75.71 grams
To find density is D = M / V
So you would have to multiply the volume by the density

the law of definite proportions states samples of a compound will always contain the same proportion of elements by mass. in other words, a given compound will always contain the same elements in the same proportions by mass.the law of multiple proportions states when two elements combine with each other to form more than one compound, then the weights of one element that combine with a fixed weight of the other are in a ratio of small whole numbers.