Answer : A - carboxyl group.
The carbon in the carboxyl group is bonded to a hydroxyl group and also it is double bonded to an oxygen group.
The carboxyl group when it is dissolved in a solution donates it's hydrogen ion(H+ ion). When it is dissolved in water, the carboxyl group loses its H+ ion to form negatively charged ion.
RCOOH + H2O⇄RCOO- + H3O+
Thus the carboxyl group act as an acid when dissolved in water.
Is a measure of how heavy atoms are. It's the ratio of the average mass per atom of an element from a given sample to 1/12 the mass of a carbon-12 atom."
In a physical change the appearance or form of the matter changes but the kind of matter in the substance does not. However in a chemical change, the kind of matter changes and at least one new substance with new properties is formed. Hope this helps!
Answer:

Explanation:
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In this case, given the T-V variation, we understand it is possible to apply the Charles' law as shown below:

Thus, since we are interested in the initial temperature, we can solve for T1, plug in the volumes and use T2 in kelvins:

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