sig figs:
ok, when you answer a question
check the number of sig figs they give you in the data.
e.g. 25.0ml of hcl solution was added to 5L of naOh 1.00000Molar solution.
you see here that it's 3,1, and 6 sig figs
your answer will be 'sigfigged' to the least number of sig figs in the data...