Why do scientists use atoms in the gas phase to measure ionization energies and electron affinities

The chart shows the bid provided by four contractors to complete a job. which contractor is the most cost-effective?

How many mmols of tris-hcl are there in 100 ml of a 100 mm tris-hcl buffer solution at ph 8.1? note that the 100 mm refers to the sum of tris and tris-hcl concentrations?

What mass of natural gas (ch4) must you burn to emit 276 kj of heat?