The total mass of the reactants equals the total mass of the products
NaOH (aq) + HCl(aq) => NaCl(aq)+ H2O(l)
Na+(aq)+ OH - (aq) + H +(aq) +Cl - (aq) + Cl- (aq)
=> Na+(aq) + Cl - (aq) + H2O(l)
H+(aq) + OH-(aq) => H2O(l)
Nitrous oxide will stay in the atmosphere the longest.
Noble gas notation for molybdenum:
[Kr] 4d^5 5s^1
We may apply a mass balance here. The total moles of NaCl will remain constant before and after the mixing of the solutions. We have three solutions:
1) 25 ml of 5 M NaCl
2) 100 ml of 0 M NaCl
3) A mixture of these solutions with volume 125 ml and concentration C
The moles of a substance are equal to the product of the concentration and volume. Thus:
25 * 5 + 100 * 0 = 125 * C
C = 1 M
The concentration of the final solution is 1 M.