It is a compound because a compound is two or more different elements chemically combined.
Answer:
(c) The retention time would be higher (d) The retention time would be lower.
Explanation:
For the polar solutes which were separated using the hydrophilic interaction chromatography (HILIC) with a strongly polar bonded phase, the retention time would be higher if eluent were changed from 80 vol% to 90 vol% acetonitrile in water.
However, for the polar solutes which were separated using the normal-phase chromatography on bare silica with methyl t=butyl ether and 2-propanol solvent, the retention time would be lower if the eluent were changed from 40 vol% to 60 vol% 2-propanol.
The scientific models are used because they allow scientists to make predictions and make it easier for scientists to avoid using data. option A and C is correct.
<h3>What are scientific models?</h3>
The scientific models are those which is given by scientists to allow them to make prediction about anything particular on which they are working or making research for it some examples are plum pudding model for an atom and bohr's model of an atom etc.
The biggest advantage is that scientists do not have to check the given data which are written into books they can perform their experiment and can conclude the data by performing experiment.
Therefore, scientific models are used because they allow scientists to make predictions and make it easier for scientists to avoid using data. option A and C is correct.
Learn more about scientific models, here:
brainly.com/question/1622233
#SPJ1
