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

Which of the following elements would you expect to have the lowest ionization energy value? fluorine, lithium, neon, nitrogen

What is the percentage of hydrogen in nitrogen trihydride

Consider hydrogen in an excited state n = 5n=5 that emits photons to reach the ground state. there are various possible transitions other than straight to the ground state that can occur; for example, it can drop to the n = 3n=3 state followed by the n = 3n=3 to the ground state transition. which of the possible transitions will result in the emission of a photon in the visible region?