Section 14.2

Boyle's Law Graphs

Stoichiometry Problems

Stoichiometry Lab

Purpose: Determine the percentage yield of a double replacement reaction

Procedure: 

1) Mass evaporating dish

2) Mass 2g Na^2CO^3 

3) Add HCL slowly until bubble stops

4) Heat until all water has evaporated

5) Mass NaCl

6) Balance the equation

Data:

Mass of evaporating dish: 46.54g

Mass of Sodium Chloride: 2.00g

Mass of NaCl: 1.67g

Calculations:

Balanced Equation: Na2CO3+2NaCl+CO2+H2O

Theoretical Yield of NaCl: 

2g Na2CO3->.0189 mol Na2CO3->.0377 mol NaCl->2.2g NaCl

Percent Yield:

1.67g/2.21g x100=75.57%yield

Conclusion:

In this lab a chemical reaction produced saltwater which was then evaporated to find the mass or yield of salt. There was significant error because the amount in the lab was only 75.57% of the theoretical yield in this equation. The error may have occurred since when heated the compound began spitting and popping, which propelled some salt out of the evaporating dish.

Practice Problem #23

Practice Problems #11-16