A compound contains only potassium and iodine. A sample weighing 12.3 g of this compound contained 2.90 g of potassium. How many grams of iodine would there be in another sample of this compound containing 9.56 g of potassium?
Do I find the mol of each (12.3 g, 2.90 g) or am I thinking wrong?
You are on the right track! To determine the number of grams of iodine in another sample containing 9.56 g of potassium, you will need to use the information from the initial sample.
First, let's find the ratio of potassium to iodine in the initial sample. Since the compound contains only potassium and iodine, the remaining mass must be iodine. Therefore, we can calculate the mass of iodine in the initial sample by subtracting the mass of potassium from the total mass of the compound:
Mass of iodine = Total mass of compound - Mass of potassium
Mass of iodine = 12.3 g - 2.90 g
Now we can find the ratio of potassium to iodine by dividing the mass of potassium by the mass of iodine in the initial sample:
Ratio of potassium to iodine = Mass of potassium / Mass of iodine
Ratio of potassium to iodine = 2.90 g / (12.3 g - 2.90 g)
Next, we can use this ratio to calculate the mass of iodine in the sample containing 9.56 g of potassium. We can set up a proportion using the known ratio:
(Mass of iodine in second sample) / 9.56 g = (Mass of iodine in initial sample) / 2.90 g
To solve for the mass of iodine in the second sample, we can cross-multiply and divide:
Mass of iodine in second sample = (Mass of iodine in initial sample / 2.90 g) * 9.56 g
Now you can plug the values into the equation and calculate the mass of iodine in the second sample.
Yes, you are thinking along the right lines. To solve this problem, you need to first determine the molar ratio between potassium and iodine in the compound, and then use that ratio to find the amount of iodine in the other sample.
Step 1: Calculate the molar mass of potassium (K) and iodine (I)
- The atomic mass of potassium (K) is 39.10 g/mol.
- The atomic mass of iodine (I) is 126.90 g/mol.
Step 2: Calculate the number of moles of potassium in the first sample.
- Given that the first sample contains 2.90 g of potassium, divide this amount by the molar mass of potassium to find the number of moles:
Moles of K = 2.90 g / 39.10 g/mol = 0.074 moles of K
Step 3: Determine the molar ratio between potassium and iodine in the compound.
- From the compound's chemical formula, you know that it contains only potassium (K) and iodine (I).
- The ratio of moles of potassium to moles of iodine can be obtained from the balanced chemical equation. However, since the compound's molecular formula is not provided, it is necessary to make some assumptions.
- For simplicity, let's assume the compound is KI, which is potassium iodide.
- In this case, the molar ratio of potassium (K) to iodine (I) is 1:1.
Step 4: Use the molar ratio to calculate the moles of iodine in the second sample.
- Since the molar ratio of K:I is 1:1, the moles of iodine will also be 0.074 moles.
Step 5: Calculate the mass of iodine in the second sample.
- Given that the second sample contains 9.56 g of potassium, you need to find the mass of iodine corresponding to 0.074 moles.
- Multiply the moles of iodine by the molar mass of iodine:
Mass of I = 0.074 moles × 126.90 g/mol = 9.39 g
Therefore, in another sample of the compound containing 9.56 g of potassium, there would be approximately 9.39 g of iodine.