Convert 1.5x10^25 atoms of hydrogen into moles of Hydrogen

How do scientists think that gravity affected the formation of our solar system?

How to convert a density of 0.791g/cm3 to lb/ft3

An engineer decides to use a slightly weaker material rather than a stronger material, since she knows that the stronger material can break suddenly. this is an example of what? a choosing a material that will show warning before it fails b using composite materials that combine strength c using a material for multiple applications d using design techniques that increase efficiency and reduce cost