Other Conversions (Volume and Heat)

So today we learned about Conversions using Volume and Heat! We already learned all those mass to moles to mass to mass shenanigans works, so we shall start fresh! D'accord?


A few points before we begin:

• Heat can be included as a separate term in a chemical reactions (Enthalpy)
• Reactions that release heat are exothermic A + B ---> C + energy
• Reactions that absorb heat are endothermic A + B + energy ---> C
• BOTH can be used in stoichiometry

LETS COMMENCE SHALL WE.......

Examples:

How many liters of oxygen are necessary for the combustion of 425 g of sulfur, assuming that the reaction occurs at STP? The balanced equation is S + O2 ---> SO2

425 g of S x 1 mol = 13.2 mol x 1 O2 x 22.4 L = 297 L

                         32.1 g                           1 S       1 mol

easy enough right? try the one on the bottom and see if you get it. The answer is underneath but you must highlight it with your mouse

How many liters of hydrogen are produced if 225 g of iron reacts with hydrochloric acid, assuming that the reaction occurs at STP? The balanced equation is:

Fe + 2HCL ---> FeCl2 + H2

Answer:  90.2 L

noice work, okay now for the iffy part... HEAT

KJ= Heat (energy)

Find the amount of heat released when 5.0 mol of H2 are consumed according to the reaction

N2 + 3 H2 ---> 2NH3 + 1( 46.2 kJ)

• first you can imagine that 46.2 kJ has a coefficient of 1 infront of it

5.0 mol x 1 (kJ) = 1.66 x 46. 2 kJ = 77 kJ

                    3                              

one more:

Find the amount of heat released when 250 g of Ammonia form according to the reaction:

N2 + 3H2 ---> 2NH3 + 1( 46.2 kJ)

Watch and learn:

250 g x 1 mol = 14.7 x 1 = 7.35 mol x 46.2 kJ 

                  17 g                       2 

= 340 kJ

THAT IS ALL! 

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