Other Conversions

• Volume at STP can be found using hte conversion factor 22.4L/mol
• Heat can be included as a seperate term in chemical reaction called enthalpy
• reaction that releases heat are exothermic
• reaction that absorbs heat are endothermic
• both can be used in stoichiometry

Examples:

- if 5.og of potassium chlorate decompose according to the reaction below, what volume of oxygen gas @STP is produced?
                                                          2 KClO3 --> 2 KCl + O2
5.0g x 1mol x 3  = 0.0612 mol x 22.4L =  1.4 L
          120.6   2                           1 mol

-When zinc reacts with hydrochloric acid exactly 1.00 L of hydrogen gas is produced at STP what mass of zinc was reacted?
                                   Zn + 2 HCl --> H2 + ZnCl2
1.00 L x 1 mol x 1 x 65.4  = 2.92 g
              22.4L   1    1mol

Nicole H