Stoichiometry & Iron Wool on Fire
Purpose of the lab:
Which is the goal in this lab?
- Aluminum foil (tray)
- ceramic pad
- Bunsen burner
- Triple beam balance
- steel wool or iron wool
Goggles, shoes, and hair tied back are required at all times during this experiment.
- Examine the steel wool. Write down its physical properties, such as: solid, liquid, or gas, texture, color, odor, etc. (This will be asked when you complete analysis question #1)
- Unroll the steel wool, pulling the strands as far apart as possible to get maximum surface exposure.
- Measure and record the mass of the aluminum tray + the ceramic protective pad.
- Place the unravel steel wool on the aluminum tray and record the mass again.
- Turn on the Bunsen burner and be sure you have a blue flame.
- Hold the fire source over the aluminum foil (to catch all product).
- Be careful; it will burn rapidly and some steel wool may break off from the bulk.
- Use the crucible tongs to move the iron wool around to be sure that all iron was burnt.
- When the reaction is over, weigh the mass of the burned steel wool on the foil.
- Calculate the mass of the burnt iron wool.
- Clean your lab station (spotless!) Cool the used steel wool and dispose in trash. Save the aluminum foil.
|Mass of Aluminum Foil + ceramic fiber mat|
|Mass of Iron Wool + Aluminum Foil + ceramic fiber mat|
|Mass of iron wool (before burning)|
|Mass of Burned Steel Wool +Aluminum Foil + ceramic fiber mat|
|Mass of Burned iron Wool|
- Describe the properties of
- Reaction in detail.
- How are the products different from the reactants?
- What happened to the mass of the steel wool?
- evidence did you see that a chemical reaction did occur?
- type of reaction occurred?
- Write a balanced chemical equation for the reaction. (Predict the formula of the product; assume iron will have a +3 charge)
- What was the limiting reactant? How do you know?
- Calculate the theoretical amount of product (in grams) based on the beginning mass of steel wool. (mass-to-mass stoich!)
- What was your percent yield of product in this experiment?
- Say you forgot to put foil beneath the steel wool as it burned. Would the percent yield be increased or decreased? Explain and show a sample calculation.
- Say you did not unravel the steel wool before burning it. Would the percent yield be increased or decreased? Explain and show a sample calculation.
- Say the steel wool is only 98 % iron. Would the percent yield be increased or decrease
Your lab report has to show the following parts:
- PURPOSE OF THE LAB
- LAB SETUP (GRAPH SHOWING THE PROCEDURES)
- DATA TABLE(S) WITH HEADINGS AND UNITS. (REMEMBER THAT TRIPLE BEAM BALANCES MUST SHOW 2 DECIMALS)
- QUESTIONS IN THE ANALYSIS
The following is a video with the calculations you need to do during the lab.