Tuesday, September 8th

I am doing this from memory at home without a book, so if I am wrong, don't kill me. Homework was pages 181-182, problems 13, 14, 15, 16, 21, 22, 23(a,b), 24(a,b), 25, 26. Bold problems were done in class. We had started 26 when time ran out. I will try and give some pointers to solve #26. The problem wanted to know the molarity of sodium ion [Na+1]. The brackets around the sodium ion symbol indicate concentration (molarity) of a particular species of compound or ion. There were two sources of sodium ion, sodium carbonate (Na2CO3) and sodium bicarbonate (NaHCO3). Each compound is soluble in water. Both compounds were given a molarity and volume, thus the moles of each compound can be found. Remember, for each sodium carbonate, there are two sodium ions. Thus the moles of sodium ion from sodium carbonate will be twice the moles of sodium carbonate. Once the moles of sodium ion are found from both sources, add them together and divide by the total volume when both solutions are added together. The concept of problem #26 will be a large concept tomorrow.