A chemist wants to make 3.1L of a 0.104M solution. How much KCl in grams should the chemist use?
How many moles will the chemist need? M x L = moles.
then moles = grams/molar mass and solve for grams.
To find out how much KCl should be used in grams, we can follow these steps:
Step 1: Determine the molar mass of KCl
The molar mass of KCl (potassium chloride) is calculated by adding the atomic masses of potassium (K) and chlorine (Cl):
Molar mass of KCl = atomic mass of K + atomic mass of Cl
Molar mass of KCl = (39.10 g/mol) + (35.45 g/mol)
Molar mass of KCl = 74.55 g/mol
Step 2: Use the formula for molarity to find the moles of KCl needed
Molarity (M) is defined as moles of solute divided by liters of solution. Rearranging the formula gives:
Moles of solute = Molarity × Volume of solution
In this case, the molarity is 0.104 M and the volume of the solution is 3.1 L. So, the formula becomes:
Moles of KCl = 0.104 M × 3.1 L
Step 3: Calculate the mass of KCl in grams
The mass of KCl in grams can be found using the following formula:
Mass (g) = Moles × Molar mass
In this case, we can calculate the mass as follows:
Mass of KCl = Moles of KCl × Molar mass of KCl
Substituting the values we obtained earlier:
Mass of KCl = (0.104 M × 3.1 L) × 74.55 g/mol
Now, let's calculate the mass of KCl:
Mass of KCl = (0.104 × 3.1) × 74.55 g
Mass of KCl = 24.2988 g
Therefore, the chemist should use approximately 24.3 grams of KCl to make a 3.1L solution with a concentration of 0.104M.
To determine the amount of KCl in grams that the chemist should use, we need to use the formula:
Amount (in moles) = Concentration (in moles/liter) x Volume (in liters)
First, let's calculate the amount of KCl in moles using the given information:
Concentration = 0.104 M
Volume = 3.1 L
Amount (in moles) = 0.104 mol/L x 3.1 L = 0.3224 mol
Now, to convert the amount in moles to grams, we need to know the molar mass of KCl. The molar mass of KCl is calculated by adding the atomic masses of potassium (K) and chlorine (Cl). The atomic masses of K and Cl are approximately 39.1 g/mol and 35.5 g/mol, respectively.
Molar mass of KCl = 39.1 g/mol + 35.5 g/mol = 74.6 g/mol
Finally, we can calculate the amount of KCl in grams:
Amount (in grams) = Amount (in moles) x Molar mass
Amount (in grams) = 0.3224 mol x 74.6 g/mol ≈ 24.01 g
Therefore, the chemist should use approximately 24.01 grams of KCl to make a 3.1L solution with a concentration of 0.104M.