Calculate the ph of each of the cases in the titration of 25ml of 0.1m of pyridine with 0.1m hbr.
calculate before addition of any hbr
after addition of 12.5ml
after addition of 18.0ml
after addition of 25.0ml
after addition of 30.0ml

Brainliesttt me asap! the below reaction can be categorized as more than one type of reaction. which reactions are these, and what are the types of reactions?

1)each group 16 element has how many valence electrons? ( )4 ( )6 ( )8 ( )16 2)how many dots appear in the dot structure for calcium ion, ca2+? ( )zero ( )one ( )two ( )eight 3) which of the following atoms forms a cation to obtain an octet of outer shell electrons? ( )magnesium ( )oxygen ( )fluorine ( )helium 4) an al3+ ion contains 13 protons and 10 electrons. ( )true ( )false 5) valence and non-valence electrons are represented in lewis dot structures. ( )true ( )false

Use examples from the article to explain one positive and one negative effect that chemistry has had on society.