A student needs to make 0.855 L of a sodium bromide solution for an experiment. The concentration of the required solution is 0.350 M. How many grams of sodium bromide will he need to use?

Explanation:

Molarity =  moles/liters of solution

moles    = molarity x Liters of solution

            =  0.350 m/L x 0.855 L

            =  0.299 mol

               mass = moles  x  molar mass    

            = 0.299 mol x 102.89 g/ms

            =  30.78 grams

i just learnt this recently but i need to look through my notes again

a gas, having a molecular weight of 13 kg/kmol and a kinematic viscosity of 0.25 cm2/s, flows through a pipe 0.25 m internal diameter and 5 km long at the rate of 0.4 m3/s and is delivered at atmospheric pressure.