Pogil- Types of Reactions

Practice Problems #12-15

Practice Problems #40 & #42

Practice Problems- #16 & 17

Balancing Equations

Percent Composition Lab

Purpose: To measure the percent of water in a series of crystalline compounds called hydrates.

Procedure:

 1) Label each test tube with the name of the compound. Measure and record the masses.

 2) Add 2-3 grams of each compound to the appropriate tube. Measure and record the mass of each test tube and compound.

 3) Heat contents of test tubes over Bunsen burner, holding at 45 degree angle. Not any changes in appearance.

 4) Heat from 2-4 minutes. Repeat steps 2 and 3 twice.

 5) Allow each tube to cool, then measure and record the mass of each test tube and heated compound.

Data: 

Calculations:

9.38g-7.58g=1.8g.     (.18g/1.8g)x100=10% water

9.69g-7.56g=2.13g.   (.58g/2.13g)x100=27.23% water

9.21g-7.58g=1.63g.   (.52g/1.63g)x100=32.9% water

Calculations Check: 

1- CaCl(2)- 

     10%=10g 

     10g (1 mol/18g)= .56 mol H(2)O

     90%=90g

     90g (1 mol/110g)= .82 mol CaCl(2)

     .8/.6=4/3 

CaCl(2)+.75 H(2)O

2- Na(2)SO(4)-

    27.23%=27.23g

    27.23g (1 mol/18g)= 1.51 mol H(2)O

    72.77%=72.77g

    72.77g (1 mol/142g)= .51 mol Na(2)SO(4)

    1.5/.5=3

Na(2)SO(4)+3H(2)O

3- Ca(2)SO(8)

    32.9%=32.9g

    32.9g (1 mol/18g)=1.83 mol H(2)O

    67.1%=67.1g

    67.1g (1 mol/240g)= .28 mol Ca(2)SO(8)

    1.8/.3=6

Ca(2)SO(4)+6H(2)O

Conclusion: 

The purpose of this lab was to find the percentage of water in various compounds through the use of evaporation and calculations. To check if answers were reasonable and accurate mole conversions were used in order to find each compound's empirical formula. Some rounding occurred, and human error such as not heating compounds long enough could have contributed to inaccuracies, but on the whole answers were as expected and fairly accurate.

Practice Problems #33-40

Practice Problems- #16-23