Experiment 16: Gravimetric Analysis for AP Chemistry
For a quick review on stoichiometry, refer to the following concepts:
- Moles, Molar Mass, and Molarity for AP Chemistry
- Percent Composition and Empirical Formulas for AP Chemistry
- Reaction Stoichiometry for AP Chemistry
- Limiting Reactants for AP Chemistry
- Percent Yield for AP Chemistry
The amount of a substance present in a sample is determined by taking a solution containing that substance and precipitating a compound containing that substance. The precipitate is then dried and weighed. (See the Stoichiometry chapter.)
- analytical balance
- crucible and cover
- drying oven
- Meker burner
- support stand
- triangle crucible support
- A sample is weighed and then dissolved.
- Excess (unmeasured) reactant is added to the solution to form a precipitate.
- The empty crucible and cover are weighed.
- The crucible and cover containing the dried precipitate are weighed.
The mass of the precipitate is found as the difference between measurements 3 and 4.
The mass of the dried precipitate is converted into moles by using the molar mass. Through use of a stoichiometric ratio, the moles of precipitate are converted to the moles of the substance of interest. The moles of this substance are converted to its mass using the molar mass.
The mass of the substance of interest divided by the mass of the sample and then multiplied by 100% gives the percent of a substance in the sample.
Common precipitates used include AgCl and BaSO4.
Today on Education.com
- Kindergarten Sight Words List
- Coats and Car Seats: A Lethal Combination?
- Signs Your Child Might Have Asperger's Syndrome
- Child Development Theories
- Social Cognitive Theory
- GED Math Practice Test 1
- The Homework Debate
- 10 Fun Activities for Children with Autism
- Why is Play Important? Social and Emotional Development, Physical Development, Creative Development
- Problems With Standardized Testing