Exam 2: The Nature of Molecules and the Properties of Water

A chemist adds a chemical to pure water and there is a 100-fold increase in the concentration of hydrogen ions.What is the best approximation of the new pH value?

The area around a nucleus where an electron is most likely to be found is the:

When two atoms share a pair of electrons,the bonding is referred to as:

Atomic nuclei contain protons and ________.

Organisms are composed of molecules,which are collections of smaller units,termed:

Magnesium chloride is a salt formed with ionic bonds between one magnesium ion and two chloride ions.Magnesium has two electrons in its outer shell and chlorine has seven electrons in its outer shell.How are the electrons transferred between these atoms?

Sugars dissolve well in water because of water's ________.

Plants transport water to their leaves through the xylem when water evaporates from the leaves.The evaporating water pulls other water molecules up the xylem through ________.

Negatively charged subatomic particles that have almost no mass are called:

Carbon has 4 valence electrons and oxygen has 6.Carbon dioxide would contain ________.

All atoms possess the ability to do work.The term that is defined as the ability to do work is:

The smallest subatomic particle is the ________.

Why is it necessary to take special safety precautions when using radioactivity?

Nitrogen has a higher electronegativity than hydrogen.As a result you would expect that ammonia (NH₃)molecules can form ________ with each other.

In the Hershey-Chase experiment,bacterial viruses,called phage,were used to demonstrate that DNA is the genetic material.The phage that were used for this experiment consisted of DNA surrounded by a protein coat.Phage will attach to specific types of bacteria and inject their DNA into the bacterial cell.To scientifically determine whether DNA is the genetic material,Hershey and Chase made phage in a medium containing radioactive sulfur-35 (S³⁵).Why was S³⁵ used in this experiment?

The electronegativity of nitrogen (N)is 3.0,while the electronegativity of hydrogen (H)is 2.1.Knowing this,consider how the electrons will be shared in ammonia (NH₃).What do you predict about the polarity of ammonia?

Atoms of a single element that possess different numbers of neutrons are called:

As you and a friend are entering a chemistry laboratory at your university,you see a sign that states: DANGER-RADIOACTIVE ISOTOPES IN USE.Your friend is an accounting major and has not had any science courses yet.She asks you what a radioactive isotope is and you respond correctly with:

The atomic number of an element is equal to the number of:

You identify an enzyme involved in a cellular reaction.How does the enzyme affect the reaction equilibrium between reactants and products and the time needed to reach equilibrium?