15. A 15.30 g sample of calcium (Ca) combines with 7.96 g of sulfur(S) to form calcium sulfide (Cas). How many grams of CaS are formed?

17.689g

Explanation:

1: First, write out the equation you will follow:

Ca + S ⇒ CaS

2: Use the formula Mass = Mr x moles to work out the moles of both Ca and S - this will enable you to find the limiting reactant.

3: Moles Ca:

Moles = mass/ Mr = 15.3/ 40.1 = 0.382 moles.

4: Moles S:

Moles = mass/ Mr = 7.96/ 32.1 = 0.245 moles.

5: We now know S is the limiting reactant, and as there is a 1:1 ratio between S and CaS, there will also be 0.245 moles CaS.

6: Mass CaS:

Mass = Mr x moles = 72.2 x 0.245 = 17.689g

each chemical family is represented as a group or column on the periodic table. based on chemical properties, there are 6 types of chemical families. group 1 represents alkali metals, group 2 represents alkaline earth metals, groups 3 to 12 represent transition metals, groups 13 to 16 represent non-metals and other metals, group 17 represents halogens and group 18 represents noble gases.

it should have an internal chamber and two thermometers sticking out of the top. the internal chamber will also be closed off from the outside.