An experiment is preformed to determin the empirical formula of a copper iodide formed by direct combination of elements. A clean strip of copper metal is weighed accurately. Its is suspended in a test tube containing iodine vapor generated by heating solid iodine. A white compound forms on the strip of copper, coating it uniformly. The strip with the adhering compound is weighed. Finally, the compound is washed completely from the surface of the metal and the clean strip is dried and reweighed.
Data Table
Mass of clean copper strip 1.2789 grams
Mass of copper strip&compound 1.2874 g
Mass of copper strip after washing 1.2748 g
a. State how you would use the data above to determine each of the following.
1.The # of moles of iodine that reacted.
2. The number of moles of copper that reacted.
B) explain how you would determine the empirical formula for the copper iodine.
C) Explain how each of the following would affect the empirical formula that could be calculated.
1. some unreacted iodine condensed on the srip.
2. A small amount of the white compound flaked off before weighing.
PLEASE HELP!!!!
An experiment is preformed to determin the empirical formula of a copper iodide formed by direct combination of elements. A clean strip of copper metal is weighed accurately. Its is suspended in a test tube containing iodine vapor generated by heating solid iodine. A white compound forms on the strip of copper, coating it uniformly. The strip with the adhering compound is weighed. Finally, the compound is washed completely from the surface of the metal and the clean strip is dried and reweighed.
Some hints below.
Data Table
Mass of clean copper strip 1.2789 grams 1
Mass of copper strip&compound 1.2874 g2
Mass of copper strip after washing 1.2748 g 3
#2-#1= mass of iodine added.
#1-#3=mass of copper reacted.
Remember that #mol = grams/atomic mass.
a. State how you would use the data above to determine each of the following.
1.The # of moles of iodine that reacted.
2. The number of moles of copper that reacted.
B) explain how you would determine the empirical formula for the copper iodine.
C) Explain how each of the following would affect the empirical formula that could be calculated.
1. some unreacted iodine condensed on the srip.
2. A small amount of the white compound flaked off before weighing.
Post your work if you get stuck. The hints I gave at the beginning should allow you to complete the questions.
I really don't understand how to do C in this question. I got a and b but im stuck on c.
The easiest way to do this is to think about what happens to the weighings. For C1. if some unreacted iodine condensed on the strip, that would make the strip heavier than it should be so mass of strip and compound would increase (what I labeled as 2 in my first response) so the mass of 2 would be higher. How will that affect the mols of copper? How will that affect the mols of iodine? How will that affect the formula?
For C2. Same idea but if some of the white compound flaked off, then the #3 weighing would be too low. How will that affect mols copper, iodine, etc.
C1: If some unreacted iodine condensed on the strip, it would increase the mass of the strip and compound (2) compared to the actual mass of the compound formed. This means that the calculated mass of iodine would be higher than the actual mass of iodine that reacted. Consequently, the number of moles of iodine calculated would be higher than the actual number of moles of iodine that reacted. This would result in an incorrect empirical formula of copper iodide when determining the ratio of copper to iodine.
C2: If a small amount of the white compound flaked off before weighing, the mass of the copper strip after washing (3) would be lower than the actual mass of the compound formed. This means that the mass of copper calculated would be lower than the actual mass of copper that reacted. Consequently, the number of moles of copper calculated would be lower than the actual number of moles of copper that reacted. This would also result in an incorrect empirical formula of copper iodide when determining the ratio of copper to iodine.
In both cases, the incorrect mass measurements would lead to incorrect calculations of the number of moles of each element and therefore an incorrect empirical formula for copper iodide.
C1. If some unreacted iodine condensed on the strip, it would increase the mass of the strip and compound (what you labeled as #2). This would affect the mols of copper and iodine that reacted.
Since the mass of the strip and compound (#2) includes both the copper and the compound, we need to figure out the mass of iodine that reacted separately.
To determine the moles of iodine that reacted, we use the formula:
Moles of iodine = (Mass of iodine added) / (Atomic mass of iodine)
So, we subtract the mass of the clean copper strip (#1) from the mass of the strip and compound (#2):
Mass of iodine added = Mass of strip and compound (#2) - Mass of clean copper strip (#1)
Then, we calculate the moles of iodine:
Moles of iodine = (Mass of iodine added) / (Atomic mass of iodine)
C2. If a small amount of the white compound flaked off before weighing, it would decrease the mass of the strip after washing (#3). This would also affect the mols of copper and iodine that reacted.
To determine the moles of copper that reacted, we calculate the change in mass of the copper:
Change in mass of copper = Mass of clean copper strip (#1) - Mass of strip after washing (#3)
Then, we calculate the moles of copper:
Moles of copper = (Change in mass of copper) / (Atomic mass of copper)
Now, to determine the empirical formula for copper iodide:
1. Calculate the moles of iodine and copper that reacted as mentioned above.
2. Find the ratio of moles of iodine to moles of copper by dividing the moles of iodine by the moles of copper.
3. Simplify the ratio to the simplest whole-number ratio by dividing each mole value by the smallest mole value.
4. Use the simplified ratio to write the empirical formula for copper iodide.
Remember that the empirical formula shows the ratio of elements in the compound, not the actual number of atoms.
C1. If some unreacted iodine condensed on the strip, it would increase the mass of the strip and compound (measurement 2 in the data table). This means that the mass of the compound will be higher than it should be, leading to an overestimation of the number of moles of copper that reacted (#1-#3 = mass of copper reacted).
To calculate the number of moles of copper that reacted, we can use the formula:
Number of moles = mass / molar mass
The molar mass of copper (Cu) is 63.55 g/mol. Subtracting the mass after washing (1.2748 g) from the mass of the strip and compound (1.2874 g), we find that 0.0126 g of copper reacted.
Number of moles of copper = 0.0126 g / 63.55 g/mol = 0.000198 mol
C2. If a small amount of the white compound flaked off before weighing, it would decrease the mass of the strip after washing (measurement 3 in the data table). This means that the measured mass of the copper strip after washing would be lower than it should be, leading to an underestimation of the number of moles of copper that reacted.
Similarly, we can calculate the number of moles of copper using the updated mass after washing. Let's say the decrease in mass due to the flaked off compound is x grams.
New mass after washing = measured mass after washing (1.2748 g) + x g
Number of moles of copper = (measured mass before washing - new mass after washing) / molar mass of copper
This decrease in the mass of the compound would affect the calculated number of moles of copper and, consequently, the empirical formula of copper iodide.
To determine the empirical formula for copper iodide (CuI), we need to compare the number of moles of copper with the number of moles of iodine. Since the experiment is based on the direct combination of elements, the empirical formula should represent the simplest whole number ratio of the elements in the compound.
Based on the calculations above, we have:
Number of moles of iodine = mass of iodine added / molar mass of iodine
The mass of iodine added can be calculated by subtracting the mass of the clean copper strip from the mass of the strip and compound.
Finally, divide the number of moles of each element by the smallest number of moles to obtain the simplest whole number ratio, which represents the empirical formula of copper iodide.
Remember to always double-check your calculations and make sure to follow the steps carefully in order to obtain accurate results. If you're still unsure or need further assistance, feel free to provide your work or any specific areas where you're having trouble, and I can offer additional guidance.