This is molarity: moles of solute/liters of solution. (Not molality)
1. Plug in what we know:
500 mL = 0.5 L
0.80 = moles/0.5
0.80*0.5 = moles
moles = 0.4
2. NaOH is given as 40 g/mole, so calculate the grams:
0.4 * 40 = 16 grams
answer: 16 grams
Humphry Davy First discovered sodium
1s^2, 2s^2, 2p^6, 3s^2, 3p^6, 3d^5, 4s^1
Chromium is strange because it moves on to the 4s orbital instead of filling the 3d orbital with that last electron. Tricky.
Mark as brainliest if this helped! :)