Item Mohs Hardness

fingernail 2.5

penny 3

knife 5.1

steel nail 6.5

You have found the mineral shown in the picture. A knife won’t scratch it, but a nail will.

Describe at least four properties that would help you identify the mineral.

Amixture with the same composition throughout is!

For the reaction shown, find the limiting reactant for each of the following initial amounts of reactants. 4al(s)+3o2(g)→2al2o3(s) a) 1 molal, 1 mol o2 b) 4 molal, 2.6 mol o2 c) 16 molal, 13 mol o2 d) 7.4 molal, 6.5 mol o2

What rule is used to determine how many covalent bonds an element can form? a. the number of covalent bonds is equal to six c the number of covalent bonds is equal to five minus the group number plus the group number b. the number of covalent bonds is equal to eight d. none of the above minus the group number select the best answer from the choices provided