Mixtures typically melt at different temperatures than the pure substances they are composed of. Brass is a mixture composed of copper and zinc, and it melts at temperatures between 820 degrees Celsius ( oC) and 1030 degrees Celsius ( oC). Why might different samples of brass melt at different temperatures? A. The samples are different in size and in volume.
B. The samples have different shapes and masses.
C. The samples are composed of different proportions of copper and zinc.
D. The samples have the same amounts of copper and zinc melting at different temperatures.

C.

Explanation:

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c

Explanation:

number of molecules / avogadro's number * molecule molecular = mass

explanation:

we define a gram-molecular weight as the mass of one mole of any element or compound. a mole contains avogadro's number of units (molecules) –  

6.022

x

10

23

. so, dividing the number of molecules by avogadro's number gives us the number of moles. multiplying that by the molecular weight gives us the mass. from the periodic table we find the gram-molecular weight of u to be238 and of f to be19. so,  

u

f

6

will have a gram-molecular weight of 352g.

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