What are the different layers of the Earth, and how do they interact?

How many liters of hydrogen gas will be produced at stp from the reaction of 7.179×10^23 atoms of magnesium with 54.219g of phosphoric acid (h3po4) the equation is 3mg + 2h3(> mg(po4)2+3h2

How many atoms are there in 5.70 mol of mg

The chart shows the bid provided by four contractors to complete a job. which contractor is the most cost-effective?