Answer:
a. The apparatus required to purify gypsum sample are: Bunsen burner, beaker, Filter Funnel, stirring rod, the filter paper.
b. Gypsum is a sulfate mineral that is made up of calcium sulfate dihydrate. Step-by-step instruction to purify gypsum sample is as follows:
1. Add water to the gypsum sample in a beaker.
2. Use the stirring rod to mix the mixture well.
3. Filter off the excess solid from the mixture using the filter paper and filter funnel.
4. Put the filtered mixture over the bunsen burner and evaporate the excess water from the mixture.
5. Allow the hot liquid to cool down and filter it again through the filter paper to get the pure gypsum.
Answer: 42.14 g
Explanation: calcium nitrate - 
, the molar mass of calcium nitrate = 164 g
<h3> formula used =

= no of moles </h3>
mass required =
=
g
Answer:
The reason is because Flagstaff is at a higher elevation than Phoenix.
Explanation:
The air is thinner at higher elevations. You can google Flagstaff's elevation compared to Phoenix but the simple answer is that air is thinner at higher elevations and some people used to 'thicker' air find it harder to breath, especially after some strenuous exercise.
The correct answer is d) chrima
First, calculating the amount of zinc carbonate by multiplying the given mass of the ore by the percent zinc carbonate.
mass of zinc carbonate = (976 tons)(0.78)
= 761.28 tons
Then, calculate for %Zn in zinc carbonate
%Zn = ((65.38) / (125.39)) x 100%
% Zn = 52.141%
tons of Zn from the sample,
mass of Zn = (761.28 tons)(0.52141)
= 396.94 tons Zn