How many moles of H2 are needed to make 15 moles of H2O?
2mol H2 + 1 mol O2 --> 2 mol H2O

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