Question

Which of the following about equilibrium constant of a reaction are true. It can change if the concentration of reactants and products are changed. It can be used to calculate the biochemical standard free energy change (Delta G degree). It can be used to calculate the actual free energy change (Delta G). It is the same as the mass action ratio (Q) when the reaction is in equilibrium. It is always a constant regardless of temperature change. Which of these statements about hydrogen bonds are true? In liquid water, the average water molecule forms hydrogen bonds with three to four other water molecules. Hydrogen bonds form as covalent bonds between positively and negatively charged ions. There is no hydrogen bond formation in liquid water at 100 degree C. Hydrogen bond is directional. Hydrogen bonds must involve at least one water molecule. Which of the following atom can serve as the hydrogen bond accentor? hydrogen carbon oxygen nitrogen sodium ions

Answer 1

Q1 (B) and (D)
Even if we change the concentration of reactants and profucts, the value of the equilibrium constant is unaffected.
There is an equation which relats the value of the equilibrium constant with biochemicalk standard free energy change. Uising a relation, we can also caluclate the standard free energy change for chemical reaction.
When a reaction is at equalibrium, the value of the equilibrium constant is also equal to the value of the mass actrion ratio (Q).
Note: The mass action ratio(Q) is also callled the reaction quotient.
The equilibrium constant value depends on vant Hoff equation. The temperature dependance of the equilibrium constant s given by the vant Hoff equation.

Q(2) (A)
A water molecule has 2 H atoms and one O atom. 2 H atoms can form H bonds with 2 other water molecules. The O atom (with 2 lone pairs of electrons) can form H bonds with 1 or 2 other water molecules.
Hydrogen bonds are not covalent bonds. They are electrostatic force of attraction between dipoles with O and H atom having partial negative and partial positive charge respectively.
Liquid water at 100 deg C can form hydrogen bond
Hydrogen bond is non directional.
Hydrogen bonds must involve atleast two water molecules.

Q(3) H atom can serve as hydrogen bond acceptor. N, O and F atoms can serve as H bond donor.