Polychlorinated biphenyls (pcbs), which were formerly used in the manufacture of electrical transformers, are environmental and health hazards. they break down very slowly in the environment. the decomposition of pcbs can be represented by the equation:

2c12h4cl6 + 23o2 + 2h2o yields 24co2 + 12hcl

a) how many moles of water are needed to react 10.0 mol o2?

b) how many grams of hcl are produced when 15.2 mol h2o react?

c) how many moles of co2 are produced when 76.5 g hcl are produced?

d) how many grams of c12h4cl6 are reacted when 100.25 g co2 are produced?

e) how many grams of hcl are produced when 2.5 kg c12h4cl6 react?

With the balanced reaction we're able to use the stoichiometric ratios in order to solve each of the questions:

2C₁₂H₄Cl₆ + 23O₂ + 2H₂O → 24CO₂ + 12HCl

a) 10.0 mol O₂ * = 0.870 mol H₂O

b) When we work with mass, we use the molecular weight:

15.2 mol H₂O * 3324.24 g HCl

c) 76.5 g HCl *   50.37 mol CO₂

d) 100.25 g CO₂ *  =68.48 g C₁₂H₄Cl₆

e) 2.5 kg C₁₂H₄Cl₆ = 2500 g C₁₂H₄Cl₆

2500 g C₁₂H₄Cl₆ * 1515.80 g HCl

hurricanes form when warm, moist air from the ocean surface quickly rises into the atmosphere and forms storm clouds and rain. when the clouds are formed, heat is released which warms the cool air in the upper regions of the atmosphere so that the cycle can continue. which two phases of the water cycle are repeated in this process?