Anugget of gold with a mass of 521 g is added to 50.0 ml of water. the water level rises to a volume of 77.0 ml. what is the density of the gold?

a). 10.4g/ml
b). 6.77g/ml
c). 1.00g/ml
d). 0.0518g/ml
e). 19.3g/ml

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.

dynamic equilibrium is the answer.