Suggested Experiments

1 You will need a UV/VIS spectrophotometer for this experiment and plastic or glass sample holders, either cuvettes or test tubes, depending on your instrument. 

A molecule absorbs radiation of frequency 3.00 x 10 Hz. What is energy difference between the molecular energy states involved  

Describe the transition that occurs when an atom absorbs UV radiation. Arrange the following types of radiation in order of increasing wavelength IR, radiowaves. X-rays, UV, and visible light. 

For a given transition, does the degree of absorption by a population of atoms or molecules depend on the number in the ground state or the excited state Explain. 

Prepare suitable standard solutions of (1) 0.1 g KMn04/L of water, (2) 1.0 g K2Cr207/L of water, and (3) water-soluble red ink diluted 50% with water. 

Measure the absorption from 700 to 350 nm and determine the wavelength of maximum absorption for each solution. 

Choose one of the standard solutions prepared in Experiment 2.1(a) and measure the 

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Standardization—External standards, standard additions, and internal standards are a common feature of many quantitative analyses. Suggested experiments using these standardization methods are found in later chapters. A good project experiment for introducing external standardization, standard additions, and the importance of the sample s matrix is to explore the effect of pH on the quantitative analysis of an acid-base indicator. Using bromothymol blue as an example, external standards can be prepared in a pH 9 buffer and used to analyze samples buffered to different pHs in the range of 6-10. Results can be compared with those obtained using a standard addition. 

The following set of suggested experiments describes the preparation of solid-state and liquid ion-exchange ion-selective electrodes, as well as potentiometric biosensors. 

The following experiments may he used to illustrate the application of kinetic methods of analysis. Experiments are divided into two groups those based on chemical kinetics and those using flow injection analysis. Each suggested experiment includes a brief description. 

Suggested experiments from the Journal of Chemical Education. Rather than including a short collection of experiments emphasizing the analysis of standard unknowns, an annotated list of representative experiments from the Journal of Chemical Education is included at the conclusion of most chapters. These experiments may serve as stand alone experiments, or as starting points for individual or group projects. 

In a prophetic vision of our physical world, Richard Feynman issued in 1959 his famous statement "There is plenty of room at the bottom". He was essentially suggesting experiments and technologies which could be performed at extremely small scales. We know nowadays that Feynman s expectations were beyond what has been achieved since he made his prediction. 

In this chapter, we have examined coupled transport systems that rely on ATP hydrolysis, on primary gradients of Na or Ff, and on phosphotransferase systems. Suppose you have just discovered an unusual strain of bacteria that transports rhamnose across its plasma membrane. Suggest experiments that would test whether it was linked to any of these other transport systems. 

Other suggested experiments include titration of 0.05M Na2C03 with 0.1M HC1, and of 0.1M boric acid in the presence of 4 g of mannitol with O.lMNaOH. 

The amygdala is perhaps the best-studied, and most strongly implicated, brain structure in anxiety and fear. Electrical stimulation of the amygdala produces fear-like behavioral and physiological responses in animals, and increases the suggestive experience of fear in human subjects. Additionally, amygdala stimulation leads to corticosterone secretion and HPA-axis activation in animals, probably via outputs to the hypothalamus and the bed nucleus of the stria terminalis. It has been suggested... 

Be familiar with all the suggested experiments. It may be that you did not perform a certain experiment, so carefully review any that are unfamiliar in Chapter 19. Discuss these experiments with your teacher. 

Many more questions will be asked than answers supplied. A number of questions will undoubtedly have answers which are obvious to readers of this paper, but it is likely that some at least will challenge their inventiveness. If the problems which are outlined provoke thoughtful discussion and suggest experiments which illuminate the issues, the purpose of this paper will be fully served. 

Computer simulations must be met with a degree of skepticism. However, these will no doubt suggest experiments aimed at confirming or perhaps disproving their conclusions. 

SUGGESTED EXPERIMENTS FOR THE CHARACTERIZATION OF THE LOW ENERGY VIBRONIC STRUCTURE... 

Table 6 Suggested Experiments for Determining Feasibility of the Drug Substance Assay Method for the Tablet Drug Product...

We concluded from these experiments that the exchange process must be occurring along the pathway to the product and the final product, once formed, is stable to the reaction conditions. Based on these results we have proposed a new mechanism which will be discussed further in the next section. We will also suggest experiments to test our new hypothesis. 

The following is a suggested experiment which will further increase your understanding of the use of normal-phase chromatography ... 

This suggests experiments in which the yield ratio is measured at different total pressures and H2-to-CO ratios. Results of such experiments are shown in Figure 7.4, in which the yield ratio is plotted versus the H2-to-CO ratio. The yield ratio is seen to be independent of total pressure at same H2-to-CO ratio, to vary linearly with that ratio, and to remain finite when extrapolated to a zero value of that ratio that is, eqn 7.36 is obeyed but eqns 7.31 and 7.35 are not. The agreement with eqn 7.36 is good confirmation of the initial assumptions, and rules out networks I and II. A discrimination between networks information at hand. 

Problem 7.5 What general conclusion must you draw from each of the following observations (a) After standing in an aqueous acidic solution, optically active C H3CH2CH0HC H3 is found to have lost its optical activity, (b) After standing in solution with potassium iodide, optically active -CoHi3CHlCH3 is found to have lost its optical activity, (c) Can you suggest experiments to test >our conclusions (See Sec. 3.29.)... 

Example 23.2 Models to Propose Experiments Impedance data obtained for PEM fuel cells often reveal low-frequency inductive loops that have been attributed to parasitic reactions in which the Pt catalyst reacts to form PtO and subsequently forms Pf " ions Suggest experiments that could be used to support or reject this model. 

Resolution of this ambiguity requires additional experiments. The processes and reactions hypothesized for a given model can suggest experiments to support or reject the underlying hypothesis. For example, the proposed formation of PtO is consistent with a... 

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