Missing question: calcium chloride dihydrate, barium hydroxide octahydrate, m<span>agnesium sulfate heptahydrate.
</span>Sodium sulfate decahydrate - Na₂SO₄×10H₂<span>O. Sodium has oxidation number +1 and sulfate -2.
</span>Calcium chloride dihydrate - CaCl₂×2H₂O. Calcium has oxidation number +2 and chlorine -1.
Barium hydroxide octahydrate Ba(OH)₂×8H₂O. Barium has oxidation number +2 and hydroxide -1.
Magnesium sulfate heptahydrate MgSO₄×7H₂O. Magnesium has oxidation number +2.
*Note: there seems to be a "typo" in the given problem. The "1000" must probably be "100" only since summing up the total number of atoms given for the different isotopes would not equal 1000 but 100 instead. Using 1000 as the basis for the mass fractions would give an answer which is 10 times less than should be.
To determine the average atomic mass of halfnium, the mass fractions of the isotopes multiplied by their respected atomic masses must all be added.
1. Determining the mass fractions (m1, m2...m5) with 100 atoms total as the basis:
m1 = 5/100 = 0.05
m2 = 19/100 = 0.19
m3 = 27/100 = 0.27
m4 = 14/100 = 0.14
m5 = 35/100 = 0.35
2. Multiplying the mass fractions with the atomic masses of the respective isotopes.
Average atomic mass of Halfnium
= (m1*176) + (m2*177) + (m3*178) + (m4*179) + (m5*180)
= (0.05*176) + (0.19*177) + (0.27*178) + (0.14*179) + (0.35*180)
= 178.55 amu
Thus, the average atomic mass of Halfnium based on the given data for its isotopes is 178.55 amu.
A electrolytic* cell that electrolysis occurs
Ex. let say you wanted traces of graphene you would set up your usual electro-chemical exfoliation rig and the graphite you submerge would be your electrolytic cell.
Hopped this helped