You are given the reaction cu + hno3 cu(no3)2 + no + h2o. which pair of half-reactions represents the balanced half-reactions for the reaction?

Oxidation reaction,Cu + HNO3 --> Cu(NO3)2

Reduction reaction, HNO3 --> NO + H2O

The reduction half reaction represents the balanced reaction as the number of Hydrogen on left side of reaction is equal to right side whereas, the nitrogen is also 1 in left side and 1 on right side

Look at the picture (it's the first option)

Explanation:

definition

                    entropy is a measure of the randomness or the extent of disorder of a chemical process.

                      enthalpy is a measure of the heat change of a reaction occurring at a constant pressure.

measurement units:

                        entropy is measured in joule per kelvin (jk⁻¹)   whereas enthalpy is measured in joule per mole (jmol⁻¹)

requirements:

                            entropy has no requirements or limits, and its change is measured by the division between the heat change of the chemical process and the temperature.

                              in contrast, enthalpy can only be related to the heat change of the reaction under standard conditions.