Why do compaines carry out a life cycle assessment on their potential new products before making them?

Assessing environmental impacts of individual products or services (we’ll call them “products” for short) is one of the most important things you can do in creating the diagnostic foundation that your company needs to pursue Eco-Advantage. Product-level impact analyses can help fine-tune your understanding of eco-related risks and opportunities, pinpoint specific areas for you to target for improvement, and help you evaluate complex options and trade-offs in product and process design. But conducting product impact assessments is tricky. There are many competing methodologies and tools available for product “life cycle analysis/assessment”

n2(g) + 3h2-> 2nh3(g)   this is the balanced equation

note the mole ratio between n2, h2 and nh3.   it is 1 : 3 : 2   this will be important.

moles n2 present = 28.0 g n2 x 1 mole n2/28 g = 1 mole n2 present

moles h2 present = 25.0 g h2 x 1 mole h2/2 g = 12.5 moles h2 present

based on mole ratio, n2 is limiting in this situation because there is more than enough h2 but not enough n2.

moles nh3 that can be produced = 1 mole n2 x 2 moles nh3/mole n2 = 2 moles nh3 can be produced

grams of nh3 that can be produced = 2 moles nh3 x 17 g/mole = 34 grams of nh3 can be produced

note:   the key to this problem is recognizing that n2 is limiting, and therefore limits how much nh3 can be produced.