Describe how the amount of air changes as you travel up through earth's atmosphere

What is the percentage by mass of silicon (si) in iron aluminum silicate (fe3al2(sio4)3)?

Consider the point on the plot where 10.0 g of naoh have been added. what amount of naoh, in moles, has been added? 0.308 mol fecl3 initially present

The speed of light is around 6.706×10^8 miles per hour. what is the speed of light in units of miles per minute?