The question is: What is the molarity of the copper (II) chloride solution your teacher provided? Show calculations. Obtain the true molarity of the copper (II) chloride solution and calculate percent error.
I have done this so far trying to answer the question:
Molar Mass: (26.98) (134.45) (63.55) (133.33)
Balanced eq: 2Al + 3CuCl2 ---> 3Cu + 2AlCl3
Mol-Mol ratio: 2 3 3 2
# of moles: 0.032 0.048 0.048 0.032
Amount: 0.86g 6.45g 3.05g 4.26g
^ (0.86g is the average mass of Al
used in the lab.)
To find percent error my teacher gave me the formula:
% Error=Value experimental-Value accepted
____________________________x100
Value accepted
My teacher also said that 0.25 M is the accepted and 0.6g is the experimental.
In this lab we put an aluminum strip into a copper(II) chloride solution to see which was the limiting reactant. I need help answering the question I wrote above. Thanks!
To determine the molarity of the copper (II) chloride solution, you need to use the information provided to calculate the number of moles of copper (II) chloride in the solution, and then divide that by the volume of the solution. Here's how you can do it:
1. Start by calculating the number of moles of copper (II) chloride using the balanced equation and the number of moles of aluminum used:
- From the balanced equation, the mole ratio between aluminum and copper (II) chloride is 2:3. Since you used 0.032 moles of aluminum, you can calculate the moles of copper (II) chloride:
Moles of copper (II) chloride = (0.032 mol Al) x (3 mol CuCl2 / 2 mol Al) = 0.048 mol CuCl2
2. Next, calculate the mass of copper (II) chloride used in the experiment:
- From the information provided, the average mass of aluminum used was 0.86 g. You can use this information to find the mass of copper (II) chloride:
Mass of CuCl2 = (0.86 g Al) x (3.05 g CuCl2 / 0.86 g Al) = 3.05 g CuCl2
3. Finally, calculate the molarity of the solution:
- Molarity is defined as the moles of solute divided by the volume of the solution in liters. The volume of the solution is not given in your question, but assuming it's given as 1.00 liter (or you have the volume), you can calculate the molarity:
Molarity = moles of CuCl2 / volume of solution
Molarity = 0.048 mol / 1 L = 0.048 M
To calculate the percent error, you'll need to compare the experimental molarity (0.048 M) to the accepted value (0.25 M), using the formula provided by your teacher:
Percent Error = (experimental value - accepted value) / accepted value x 100
Percent Error = (0.048 M - 0.25 M) / 0.25 M x 100 = -80.8%
The negative sign indicates that the experimental value is lower than the accepted value, and the large percent error suggests there may have been some errors or uncertainties in the experimental procedure or measurements.