Answer:
119.85 grams Br or 120. grams Br (sig figs)
Explanation:
1.50 moles Br 79.90 g Br
--------------------- x ------------------------ = 119.85 grams Br or 120 grams Br (sig figs)
1 mole
Molality is defined as the number of moles of solute in 1 kg of solvent.
molality of solution to be prepared is 0.50 molal
this means that in 1000 g of water there should be 0.50 mol of NaCl
if 1000 g of water should contain - 0.50 mol
then 750.0 g of water requires - 0.50 mol/kg x 0.750 kg = 0.375 mol
mass of NaCl in 0.375 mol - 58.5 g/mol x 0.375 mol = 21.9 g
therefore a mass of 21.9 g of NaCl is required
Volume of a cylinder: V= pi (r)^2(h)
B) 0.670 L ..............................