How many moles of oxygen gas would be needed to react with 155 g of propane gas, C3Hg, in a combustion reaction?
C3H8 (g) + 502 (g)
+
-> 3CO2 (g) + 4H20 (1)

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