You are asked to make a 0.3M CaCl2 solution in a flask that can hold
200 ml. How would you do it?
How many moles do you want? That's M x L = mols.
How many grams is that? That's mols = grams/molar mass. Calculate grams.
Weigh the grams, add to the 200 mL volumetric flask, add some water, swish to dissolve the solid, make to the mark with distilled water and mix thoroughly.
To make a 0.3M CaCl2 solution in a 200 ml flask, you would need to follow these steps:
1. Calculate the amount of CaCl2 needed:
The molarity (M) of a solution is defined as the number of moles of solute per liter of solution. In this case, the desired molarity is 0.3M, which means there are 0.3 moles of CaCl2 in 1 liter of solution.
To calculate the amount of CaCl2 needed for a 0.3M solution in a 200 ml flask, we need to convert the volume of the flask from milliliters to liters. Since there are 1000 ml in 1 liter, the volume of the flask in liters is 200 ml / 1000 ml/L = 0.2 L.
Therefore, you need 0.3 moles/L * 0.2 L = 0.06 moles of CaCl2.
2. Determine the molecular weight of CaCl2:
The molecular weight of a compound is the sum of the atomic weights of all the atoms in the molecule. CaCl2 consists of 1 calcium atom (Ca) and 2 chlorine atoms (Cl). The atomic weights are approximately 40 g/mol for calcium and 35.5 g/mol for chlorine.
Therefore, the molecular weight of CaCl2 is 40 g/mol + (35.5 g/mol * 2) = 111 g/mol.
3. Calculate the mass of CaCl2 needed:
To calculate the mass of CaCl2 needed, we can use the formula: mass = number of moles * molecular weight.
In this case, the mass of CaCl2 needed is 0.06 moles * 111 g/mol = 6.66 grams (rounded to two decimal places).
4. Weigh out the required amount of CaCl2:
Using a balance, measure out 6.66 grams of CaCl2. Make sure to handle the chemical safely and wear appropriate protective equipment.
5. Dissolve CaCl2 in the flask:
Add the measured amount of CaCl2 to the 200 ml flask. Then, slowly add distilled water to dissolve the CaCl2 and fill the flask to its capacity. Make sure to dissolve all the CaCl2 completely.
Now, you have successfully made a 0.3M CaCl2 solution in a 200 ml flask.
To make a 0.3M CaCl2 solution in a 200 ml flask, you will need to find out the amount of CaCl2 needed. Here's how you can do it:
1. Determine the molar mass of CaCl2 (calcium chloride). The molar mass of Ca is approximately 40.08 g/mol, and the molar mass of Cl is approximately 35.45 g/mol. Since CaCl2 contains two Cl atoms, the total molar mass is calculated as follows:
Molar mass of CaCl2 = (1 * molar mass of Ca) + (2 * molar mass of Cl)
= (1 * 40.08 g/mol) + (2 * 35.45 g/mol)
= 111.02 g/mol
2. Calculate the number of moles of CaCl2 needed to make the desired concentration:
Moles of CaCl2 = (desired concentration in M * volume in liters)
= (0.3 mol/L * 0.2 L)
= 0.06 mol
3. Calculate the mass of CaCl2 needed using the molar mass and the number of moles:
Mass of CaCl2 = (number of moles * molar mass)
= (0.06 mol * 111.02 g/mol)
= 6.66 g
4. Weigh out 6.66 grams of CaCl2 using a scale that can measure to the nearest hundredth of a gram. Transfer the weighed CaCl2 into the empty 200 ml flask.
5. Add distilled water to the flask gradually while stirring to dissolve the CaCl2 completely. Make sure the total volume doesn't exceed 200 ml. You may need to adjust the amount of water added depending on the final volume you achieve after dissolving the CaCl2.
6. Once the CaCl2 is fully dissolved, the solution will be a 0.3M CaCl2 solution in the 200 ml flask. Make sure to label the flask with the concentration and contents for future reference.
Remember to use caution while working with chemicals and always follow proper laboratory safety protocols.