Blog

A hydrogen fuel cell operates with the following reaction taking place at the anode: 2H2(g) + 4OH−(aq) → 4H2O(l) + 4e− What volume of H2 gas at 25°C and 170 atm is required for the fuel cell to run a motor drawing 8.5 A for 4.0 hours?            (1) 0.045L       (2) 0.091L      (3) 0.18L             (4) 0.36L         (5) 0.72L

For the electrochemical cell Pt(s) | H2(1 atm) | H+(1 M) || Cu2+(1 M) | Cu(s), which one of the following changes will cause an increase in the cell voltage?  (1) Lower the H2(g) pressure.(2) Lower the H+(aq) concentration.            (3) Increase the size/mass of the copper electrode.   (4) Decrease the concentration of Cu2+ ion.            (5) None of the above.  

A researcher uses antibody staining to observe the plasma membrane of a cell, but notices that most of the sample looks fluorescent, not just the membrane, making it hard to distinguish. What could have caused this?

In immunoassay procedures such as ELISA, Tween 20 (T20) is used to:

Which one of the following is not obtained from the electrolysis of an aqueous solution of NaCl? (1) NaOH         (2) Cl2             (3) H2              (4) Na   

According to Le Chatelier’s principle and the dependence of free energy on reactant and product concentrations, which statement is true? (Assume that both reactants and products are gaseous.)

A researcher conducted a study to determine the effects of insulin concentration on the adipogenesis of fibroblast cells. The absorbance of light by the dye OPD is directly proportional to the number of fat produced.  Interpret the results provided in the graph below and write a paragraph as if it were the Interpretation section of the lab report. Make sure to include the following information:   1. What is the effect of the different insulin concentrations in the fat produced by the adipocytes? 2. Provide a possible explanation for the results observed when insulin concentration increased from 1 to 4 ug/mL.     

The following are metal pairs representing electrodes in theoretical voltaic cells. Which pair is incorrectly labeled?        (1) Ag, oxidized/ Cu, reduced                    (2) Ag, oxidized/ Au, reduced (3) Ni, reduced/ Al, oxidized                        (4) Cu, reduced/ Pb, oxidized         (5) Na, oxidized/ Mg, reduced

Consider the following reaction at 25°C and select the false statement from below. Mg(s) + Fe2+ (aq) ⇋  Mg2+ (aq) + Fe(s)          (1)  E° > 0          (2)  ΔG° < 0            (3)  K > 1     (4)  Mg is a stronger reducing agent than Fe          (5) Mg2+ is a stronger oxidizing agent than Fe2+

True or False:   Microglia conduct and transmit information to other cells.