Aconversion factor is a fraction that is always equal to what number

Which statement is true about ionic compounds?

An empty fuel tank can still contain and therefore can be even more dangerous than one full of liquid fuel.

Imagine that twenty i.u.’s of enzyme z were catalyzing the above reaction for one minute, under vmaxconditions, in a 3.00 ml assay volume. the assay is buffered with 20 mm phosphate buffer, ph 7.60. what will the ph be at the end of that one minute?