Plz plz plz help my brain cells are dying

Pegmatites are igneous rocks in which the individual minerals are very large. typically, the minerals are all light-colored quartz, feldspar and muscovite. if you were given a black and white photograph of a pegmatite in a quarry (where the rock has been blasted and broken), what physical properties could you use to identify those three minerals in this hypothetical photo? describe each mineral and the specific diagnostic properties. be specific.

How many moles of lead are in 1.50 x 10^12 atoms of lead? could you explain the answer as well and not just give it to me i am refreshing for finals and i need to know how to do it

A20 liter cylinder of helium at a pressure of 150 atm and a temperature of 27°c is used to fill a balloon at 1.00 atm and 37°c. what is the volume of the balloon? a. 0.14 liters b. 3000 liters c. 2900 liters d. 2400 liters e. 3100 liters