1. A sample of a gas is called ethane is analyzed and found to be 80.0g carbon and 20.0g hydrogen. What is the empirical formula for this compound?

2. A compound contains 31.2% Ca, 18.8% C, and 50.0% O. What is the empirical formula for the compound?

3. Determine the empirical formula for a compound that is composed of 43.7% phosphorus and 56.3% oxygen.

4. What is the empirical formula for a sample that contains 44.3g copper and 55.7g bromine?

5. Calculate the percentage of water in the hydrate manganese (II) nitrate tetrahydrate. (Hint: Do you need to write the formula for the hydrate?)

answer is: naturally occurring solid, inorganic compound or element is mineral.

minerals usually have crystalline form, that means than crystal constituents (atoms, molecules or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions.

for example magnetite is a mineral of iron oxide (fe₂o₃).

calcite is a carbonate mineral and the most stable polymorph of calcium carbonate (caco₃).

dolomite is an   carbonate mineral composed of calcium magnesium carbonate (camg(co₃)₂).

the answer is b because, investigating whether another species of moth also drinks tears might be interesting, but it would not directly explain why this species of moth does.

to explain why this species of moth drinks tears, the scientist could ask: "what nutrients that moths need are in elephant tears? "

the scientist could experiment with moth repellent or oter ways to keep the moths away, but that would not answer his original question.