the amount of K2Cr2O7 required to prepare 100ml of its 0.05N solution
0.2452g
how to make Potassium Dichromate 0.05N 1tr
To determine the amount of K2Cr2O7 required to prepare a 0.05N solution in 100ml, we need to follow a step-by-step process involving a series of calculations. Here's how you can get the answer:
Step 1: Understand the concept of Normality (N):
Normality (N) is a unit of concentration that represents the number of equivalents of a substance per liter of solution. In this case, the given concentration is 0.05N.
Step 2: Find the molar mass of K2Cr2O7:
K2Cr2O7 is composed of two potassium atoms (K), two chromium atoms (Cr), and seven oxygen atoms (O). The atomic masses are as follows:
- K: 39.10 g/mol
- Cr: 52.00 g/mol
- O: 16.00 g/mol
Therefore, the molar mass of K2Cr2O7 can be calculated as follows:
Molar mass of K2Cr2O7 = (2 * molar mass of K) + (2 * molar mass of Cr) + (7 * molar mass of O)
Step 3: Calculate the equivalent weight of K2Cr2O7:
The equivalent weight is the molar mass of a substance divided by its valence. For K2Cr2O7, the valence is the number of electrons gained, lost, or shared when the compound is involved in a chemical reaction. In this case, K2Cr2O7 is a salt, so its valence is equal to the total charge on the ion.
The valence of potassium (K) is +1, and the valence of dichromate (Cr2O7) is -2. Therefore, the valence of K2Cr2O7 is determined as follows:
Valence of K2Cr2O7 = (2 * valence of K) + (valence of Cr2O7)
Next, we calculate the equivalent weight using the molar mass and valence:
Equivalent weight of K2Cr2O7 = Molar mass of K2Cr2O7 / Valence of K2Cr2O7
Step 4: Calculate the amount of K2Cr2O7 required:
To calculate the amount of K2Cr2O7 needed, we use the formula:
Amount (in moles) = Normality (N) * Volume (in liters) * Equivalent weight
Since the volume is given in milliliters, we need to convert it to liters:
Volume (in liters) = Volume (in milliliters) / 1000
Finally, substitute the values into the formula to calculate the amount of K2Cr2O7 required:
Amount (in moles) = 0.05N * (Volume (in milliliters) / 1000) * Equivalent weight
By following these steps, you can calculate the amount of K2Cr2O7 required to prepare a 0.05N solution in 100ml.
According to question normality is equal to a
Technically one cannot calculate a normality without knowing the reaction.
USUALLY K2Cr2O7 goes to 2Cr^3+.
So equivalent weight K2Cr2O7 = molar mass/6 = 294.18/6 = 49.03. I don't expect you will have seen this equation but keep it in mind; it can help you many times in the future.
mL x N x milliequivalent weight = grams.
You know mL, N, and mew; solve for grams.