Answer:
4423.08 L
Explanation:
First we need to know the concentration of sodium per litre (as the density is 1 g/L, 1 g of water is the same that 1 mL of water) of softened water by dividing the percentage in 100:

With the value of concentration, we just need to to divide the recommended value of the FDA, that is 2300 milligrams per day, into the concentration that we have, therefore:

Answer:
the ion will have additional 2 electrons so it will be 18
An environmental scientist studies the environment - you can see that in the beginning of the sentence :)
Answer:
0.940mol &
0.000301mol respectively.
Explanation:
number of moles = given mass / molar mass
given mass of Nacl = 55g Molar mass = 23 + 35.5
n=m/M = 55g/58.5g/mol = 0.940mol
note- (add the atomic weights of sodium and chlorine to get the molar mass of Nacl.) = 58.5g/mol
similarly, NaCO3 = 23 + 12 + 16*3 = 83g/mol
n=m/M = 0.025g/83g/mol = 3.01 * 10^-4 = 0.000301mol
extra: If you ever get asked to put it in number of particles just use the relation of 1mole = 6.02 * 10^23 particles.