19. A 50.0mL sample of 2.00MHNO3 solution is treated with 2.42g of magnesium. Calculate the concentration of HNO3 after all the metal has reacted. Assume the volume of the reaction stays the same throughout. The unbalanced reaction is HNO3(aq)+Mg(s)Mg2(NO3)2(aq)+H2(g) a. 0.00900M b. 0.000450M c. 0.100M d. OM (all HNO3 used up) 20. Potassium has three naturally oceurring isotopes K39(93.26%,38.964amu),K40 (0.0117%,39.964amu) and K41(6.73%). Calculate the isotopic mass of K41 to two decimal places. a. 40.97amu b. 30.53amu c. 41.90amu d. 39.10amu