Copper (II) bromide is used as a wood preservative. What mass of CuBr2 is needed to prepare 750.0 mL of a 1.25 M solution?

Answer:209.53

Explanation:

Molar concentration=moles/Volume. Volume is given as 750mL which can be converted as 0.75l, so moles of CuBr2 is molar concentration * Volume = 1.25*0.75=0.9375

Mole = mass of CuBr2/molecular Mass of CuBr2.

Molecular Mass of CuBr2 is 63.5+80*2=223.5 (mass number of Cu=63.5 and Br=80).

So mass required = 223.5*0.9375=209.53g

238.2 g of CuBr₂ is the mass needed

Explanation:

To work with molarity and volume, we can find the mass of solute as this

Molarity. volume (L) = moles → moles. molar mass = mass

1.25 mol/L. 0.750L = moles

0.9375 moles

0.9375 mol. 223.35 g/mol = 238.2 g of salt