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Which access control model bases access decisions on the user’s role in the organization?   

An action potential has five parts. List them. Five points.

Which of the following are true?  Choose all that apply.

Find the correct coefficients so that the following equation balances.  Some answers may be used more than once, some may not be used. ____ Mg(s) + _____ Cr3+(aq) –> ____ Mg2+(aq) + _____ Cr(s)

Choose the best labels for the diagram of an electrochemical cell. electrochemical_cell_labsl.png 

Complete the following passage with the best answers.  Some answers may be used more than once, some may not be used.   The strength and concentration of acids and bases can be measured in multiple ways.  Perhaps the simplest, oldest, and most common methods involve the use of pH 1)____________________, which change color in the presence of acid or base.  One type is called 2)____________________ paper, which generally changes to blue in the presence of base, and pink (or red) in the presence of acid.  Another type, which goes by the generic name of 3)_________________________ uses several different compounds which change color at different pH values, generating a spectrum of different colors and allowing a more accurate estimate of the pH of the solution.  For even more precise results, a digital 4)________________________ can be used, which is an electronic instrument with an electrode that is immersed in the solution to give a digital readout of pH.  Such instruments do require frequent calibration, however.  A different sort of measure involves an actual stoichometric experiment — in a 5)_______________________, a solution with a very precisely known concentration is reacted with the unknown acid or base until the exact point of complete reaction is reached, at which point the volume and concentration are used to calculate the concentration of the unknown.  In such an experiment, a common visual indicator known as 6)________________________ can be used, which changes color from clear to a purple-pink color very close to neutral pH, with the pink color seen in the basic pH range and clear when the solution is acidic.

Which of the following molecules have a net dipole moment?  Choose all that apply.

Complete the following passage with the best answers.  Some answers may be used more than once, some may not be used. Acids and bases can be strong or weak, and in their stronger forms can be highly 1)__________________, capable of causing chemical burns and degradation to many kinds of materials, including metals and biological tissues.  However, acids and bases can neutralize eachother, and generally form harmless, inert products like water and 2)_________________.  The behavior of acids and bases depends on the concentration and 3)__________________ of the acidic or basic species.  Historically, there have been a number of ways that acids and bases have been defined.  The 4)_________________ definition states that acids produce H+ in solution, bases produce OH- in solution.  These sorts of acids and bases are 5)__________________, in that they dissociate in solution to form ions (H+ and OH-).  In most such acids, the ionizing hydrogen is bonded to a highly 6)________________ atom such as Cl, Br, F, or O, which dissociates to form H+ and an anion.  In aqueous solution, H+ is stabilized by complexes with water such as H3O+ — also known as the 7)______________ ion — and others.  H+ is often referred to simply as a proton; gain of H+ is known as 8)____________________, loss of H+ as 9)__________________.  Bases similarly dissolve to form OH-; metal hydroxides are very common and form OH- and M+ upon dissociation.  By the latter 10)__________________________ definition, acids donate H+, and bases accept H+.  By this definition, ammonia exhibits basic behavior by accepting H+; it is also sort-of a base by the earlier definition, because it reacts with water to form OH-.

The three primary phases of ordinary matter are solids, liquids and gasses. 1)_____________________ are characterized by having their atoms located in fixed positions; in the 2)_______________________ phase, particles experience significant attraction to one another and are located close together, but not in fixed positions such that they can slide past one another; in the 3)__________________ phase, particles do not experience enough attraction to one another to stay together, and move independently with little interaction. Transitions between phases of matter are often possible with changes in 4)_________________. As heat energy is added, particle movement increases, and as attractive forces are overcome, solids can transition to liquids and liquids to gasses. The stronger the attractive interactions are, the more energy is required, resulting in higher 5)____________________________ points.

Which pairs of elements show the proper order of electronegativity, with the most electronegative atoms or elements further to the left?  Choose all that apply.