Which statement describes the structure of an atom? 1. The nucleus contains positively charged electrons
2. The nucleus contains negatively charged electrons
3. The nucleus has a positive charge and is surrounded by negatively charged electrons.
4. The nucleus has a negative charge and is surrounded by positively charged electrons.

10-14. (a) when 100.0 ml of weak acid ha were titrated with 0.093 81 m naoh, 27.63 ml were required to reach the equivalence point. find the molarity of ha. (b) what is the formal concentration of a- at the equivalence point? (c) the ph at the equivalence point was 10.99. find pk. for ha. (d) what was the ph when only 19.47 ml of naoh had been added?

What are scientists who study fossils called? ( a ) astronomers. ( b ) biologists. ( c ) geologists. ( d ) paleontologists.

The chemical bond connecting one nucleotide with the next one along the nucleic acid chain is called a