Answer:
D, Li2S
Explanation:
This is because Lithium, which is in group IA of the periodic table, has a charge of +1. Sulfur will have a charge of -2 because it is in group 6A in the periodic table, which means to balance these out, there needs to be 2 lithium ions which would result in a charge of +2. With Lithium now having a charge of +2 due to having two atoms in the compound, and sulfur already having a charge of -2 as one atom, these two cancel out meaning the compound is neutral.
The mass of the water is 1.20 - 0.80 = 0.40 grams.
The % of water is (0.40 / 1.20 ) * 100 = 33 1/3%
It makes an ecosystem stable
Solid , solid, partially melted, liquid so the answer is D