Describe exactly how you would make 150.0g of a 4.00% (w/w) solution of NaBr in water ?

Answer 1

4.00% w/w means 4.00 g NaBr in 100 g soln. You want 150 g soln; therefore,
4.00g NaBr x (150g/100g) = 6.00 g NaBr/150 g soln.
I would do it this way. Weigh exactly 6.00 g NaBr and place it in a container. Tare the container containing the NaBr on a balance and add water until the balance reads 150.0 grams. Check you calculations.
(mass NaBr/mass soln)*100 = (6.00/150)*100 = 4.00%

Answer 2

What is the mass in grams of one mole of water

Answer 3

Sorry I thought I was posting a question not an answer to your question!!