Mole Ratios In A Chemical Reaction Lab

Shayna Salloway
AP Chemistry A
Snyder
11 September 2014

Title: Finding Mole Ratios of Reactants in a Chemical Reaction
Purpose: Experiment using the method of continuous variations to figure out mole ratios of reactants.
Procedure:
1. Take the NaClO and the sodium thiosulfate solutions and measure the temperature of each solution. Record in the data table.
2. Mix a combination of the NaClO and the thiosulfate solution equal to 50 ml in a Styrofoam cup, stir with thermometer, and record temperature in the data table. Dispose of solutions and rinse cup well. Continue taking data until you have enough data to record and make a thorough graph.
3. Plot your data to create two lines with an intersection on a graph. Repeat any measurements that do not fall near the best-fit line. From the intersection, calculate the mole ratio of the reactants.
Data Table:
Experiment ml NaClO ml Solution B Temperature of Precipitate (degrees)
1 5 45 27.0
2 15 35 35.0
3 25 25 44.0
4 30 20 49.0
5 35 15 52.0
6 40 10 46.5
7 50 0 24.0
8 45 5 22.0
9 43 7 21.0

Graph:
I eliminated the last two data points because it was making my graph weird. 20 ml of NaClO is equal to 30 ml of solution B, 40 ml of NaClO is equal to 10 ml of solution B, etc.

Mole Ratio:
Intersection is at (35, 15) → 35/15= 2.333…
__2__NaClO + __1__ Solution B → Products

Which reactant is the limiting reactant along the upward sloping line of your graph? Which reactant is the limiting reactant along the downward sloping line? Explain how you made this determination. Sodium hypochlorite is the limiting reactant along the upward sloping line and Solution B is the limiting reactant along the downward sloping line. I made this determination by looking at the graph; NaClO is the limiting reactant, as the best-fit line rises you can see that all of it gets used up as it makes the incline. Solution B is the limiting reactant along the downward slope because, looking at the graph, you can see it gets used up in the