MultiStep Conversions

MASS    <-------->      MOLES  <-------->    VOLUME(@STP)
               molar mass          |         mass volume
                                          |
                                          |
                                MOLECULES   ( Avogardo's number)
                                          |
                                          |
                                    ATOMS     ( subscripts)

 Remember : when you are converting, you must always go back to moles first!
                          ** with the exception of molecules to atoms or atoms to molecules

EXAMPLES:

- 11.5g of H2 gas are placed in a balloon at STP. Determine the volume of the balloon.

(there is 2 ways to do this)

1.)   step 1 : 11.5g x 1mol    = 5.75 mol
                    2.0g 
   
        step 2 : 5.75 mol x 22.4 L    = 128.8 = 129 L    (*dont forget your significant digits)
                                      1 mol
                                     
                                       OR
2.)   11.5g x 1 mol      x   22.4 L   = 129 L
                    22.4 L         1 mol



REMEMBER TO STUDY FOR YOUR MIDTERM !!!

Nicole H