Saline solution for intravenous drips have a NaCl concentration of 0.90 m/m . Calculate the mass of salt needed to make 500 g of saline fluid.

Answer 1

That is supposed to read 0.9% (m/m). This means there will be 0.9 g NaCl/100 g of solution. In fact, in the real science world, normal saline is not 0.9% (m/m), but rather is 0.9% (m/v), but that's an aside. To answer the question as written, you have 0.9 g NaCl/100 g solution. So for 500 g solution you need 5 times that.

0.9 g/100 g solution x 500 g solution = 4.5 g NaCl needed.