Question

water is an excellent solvent. select the property that justifies this statement.
as a polar molecule, it can surround and dissolve ionic and polar molecules.
it is liquid and will adhere to many substances
it forms ionic bonds with ions, hydrogen bonds with polar molecules, and hydrophobic interactions with nonpolar molecules.
it forms hydrogen bonds with itself so cohesion is possible.
what is the effect of an enzyme on the energy of a chemical reaction?
enzymes decrease the free energy of the reactants.
enzymes decrease the difference in energy between products and reactants.
enzymes decrease the activation energy of the reaction.
enzymes increase the free energy of the products.

Explanation:

• For the first question: Water is a polar molecule. Polar molecules can interact with ionic and other polar molecules. The "like - dissolves - like" principle explains that polar solvents (water) can dissolve polar and ionic solutes. The other options are incorrect. Just being a liquid (second option) doesn't fully explain its solvent property. Water doesn't form ionic bonds with ions (third option, it forms ion - dipole interactions). Cohesion (fourth option) is about water - water interactions and not directly about its solvent property.
• For the second question: Enzymes are biological catalysts. Catalysts work by lowering the activation energy of a chemical reaction. The free energy of reactants and products is determined by their nature and is not changed by an enzyme (first and fourth options are wrong). The difference in energy between products and reactants (the change in free energy of the reaction) is also not changed by an enzyme (second option is wrong).

Answer:

• First question: As a polar molecule, it can surround and dissolve ionic and polar molecules.
• Second question: Enzymes decrease the activation energy of the reaction.