If you do an absorbance reading after plasmid purification and get a A260/A280 of less than 1.8, how could you further purify the sample to get rid of the protein contamination

The modern periodic table has groups.

You encounter a solution that is acidic and you decide to test it by adding a small amount of a strong acid. the ph lowers slightly but is approximately unchanged, and still remains acidic. what can you say about the solution? a. it is a buffer solution. b. it is not a buffer solution it is a strong acid solution. d. the solution has been neutralized. e. the solution has excess acid present

Which best explains why an iceberg floats?