How many milliliters of an aqueous solution of 0.219 M magnesium bromide is needed to obtain 10.1 grams of the salt ?
1. Divide 10.1g MgBr2 by the fomrula mass of MgBr2 to get the moles
2. Substitute the value for moles and molarity into:
moles = molarity x liters
Solve for liters and then convert the liters to milliliters.
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To find the volume of the aqueous solution needed, we can use the formula:
moles = mass / molar mass
First, let's calculate the moles of magnesium bromide using the given mass:
moles of magnesium bromide = mass of magnesium bromide / molar mass of magnesium bromide
The molar mass of magnesium bromide can be calculated by adding the molar masses of magnesium and bromine, where:
molar mass of magnesium (Mg) = 24.31 g/mol
molar mass of bromine (Br) = 79.90 g/mol
molar mass of magnesium bromide (MgBr2) = 2 * molar mass of bromine + molar mass of magnesium
Next, we can calculate the moles of magnesium bromide:
moles of magnesium bromide = 10.1 g / molar mass of magnesium bromide
Now, we can find the volume of the aqueous solution needed. Since the given solution has a concentration of 0.219 M (moles per liter), we can use the formula:
volume (in liters) = moles / concentration
However, we need the answer in milliliters, so we'll convert the volume to milliliters:
volume (in milliliters) = volume (in liters) * 1000
Let's calculate:
Step 1: Calculate the molar mass of magnesium bromide:
molar mass of magnesium bromide = 2 * molar mass of bromine + molar mass of magnesium
molar mass of magnesium bromide = 2 * 79.90 g/mol + 24.31 g/mol
Step 2: Calculate moles of magnesium bromide:
moles of magnesium bromide = 10.1 g / molar mass of magnesium bromide
Step 3: Calculate the volume of the solution:
volume (in liters) = moles of magnesium bromide / concentration
volume (in liters) = moles of magnesium bromide / 0.219 M
Step 4: Convert the volume to milliliters:
volume (in milliliters) = volume (in liters) * 1000
By following these steps and performing the calculations, you will be able to find the answer to your question.