Exam 2: Water and Carbon: the Chemical Basis of Life

A pH of 7 is neutral due to the dissociation of water molecules in pure water.How many molecules of water have broken down into a hydroxide ion and a hydronium ion at pH 7?

During chemical evolution,which of the following occurred in the molecules involved?

Why are some reactions exothermic?

A solution with a pH of 5 has how many more protons in it than a solution with a pH of 7?

In the Gibbs free-energy relationship,why is the T term necessary?

If an atom has a charge of +1,which of the following must be true?

How many electrons are involved in a double covalent bond?

When are atoms most stable?

Which of the following tends to make chemical reactions spontaneous?

Which of the following is not a property of liquid water?

How can you determine the approximate mass of an atom in atomic mass units?

There are four elements that make up 95% of all matter found in organisms.Which of the following is not one of these?

Consider the following reaction at equilibrium: CO₂ + H₂O ↔ H₂CO₃.What would be the effect of adding additional H₂CO₃?

The Q10 rule states that,within their survivable range,the rates of biochemical processes of many ectothermic organisms approximately double with every 10-degree (C)rise in temperature.Why would this be true?

How many electrons are involved in a triple covalent bond?

How many times can humans be sure the switch from nonlife to life has happened in the universe?

If an atom has a charge of -2,which of the following must be true?

The difference between a polar covalent bond and an ionic bond is that electrons are shared unequally in a polar covalent bond,but are completely transferred (i.e.,not shared)in an ionic bond.

Nitrogen (N)normally forms only three covalent bonds because it has a valence of five.However,ammonium has four covalent bonds,each to a different hydrogen (H)atom (H has a valence of one).Make a sketch of this molecule.Count the number of electrons in your sketch.Compare this number to the number of valence electrons in one N and four H's.What is the charge on this molecule most likely to be?

While water has many exceptional and useful properties,which is the rarest property among compounds?