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What mass of KBr (in grams) do you need to make 250. 0 mL of a 1. 50 MKBr solution?.

User Robert Metzger
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1 Answer

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20 votes

Answer:

KBr final solution:

V = 250mL --> 0.25L

Concentration/Molarity = 1.5 mol/L

To find the amount of moles of KBr here, just multiply the volume by the concentration (0.25 x 1.5 = 0.375 mol)

So the amount of moles for KBr is 0.375 mol. Now we know that the mass divided by the molar mass (the atomic mass values of K and Br in the periodic table added together) would give us the amount of moles aswell.

n = moles

m = mass

M = molar mass

n = m/M

so if we rearrange this equation to find mass, we would get:

m = n x M

Molar mass for KBr: (39.09) of K + (79.90) of Br = 118.99

m = 0.375 mol x 118.99

m = 44.62g

Therefore 44.62g of KBr is needed to make 250mL of a 1.5 M KBr solution.

User Craastad
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