Ten Experiments

70 do these experiments, you should always wear some form of eye protection so you can protect your eye sight in the event of any unwanted spills or reactions. You should also wear closed-toed shoes so that spillages do not hurt your feet and toes. You should always start with small amounts when mixing chemicals to avoid any large mishaps. All of these experiments can be carried out at home, or they could be used as a chemistry demonstration in a classroom. 

Using some common household products and practicing some kitchen chemistry, you can perform some pretty interesting inorganic chemistry experiments. In this chapter, we describe ten easy-to-perform inorganic chemistry experiments. 

There s a chemistry battle between starch and vitamin C. The starch wants to turn blue as it s reduced, but the vitamin C keeps it from being reduced and turning blue. Eventually, an iodine starch complex forms and gives the solution a blue color. In this experiment, you change the amount of time it takes for the liquids to change color. 

Start by crushing up a vitamin C tablet into a powder. Add it to 2 ounces (60 mL) of warm water and stir it for 30 seconds. Transfer 1 teaspoon (5 mb) of the vitamin and water mixture into a new cup and then add 2 ounces (60 mL) of warm water + 1 teaspoon (5 mb) of iodine (tincture of iodine 2% concentration). This should make the iodine solution turn clear. In another clean 

Put a teaspoon of baking soda into a glass jar and then place a lit candle on top. Add some water to the baking soda, but be careful not to put out the flame in the candle. As the water reacts with the baking soda, it produces carbon dioxide and this can t combust (not without a catalyst present). Increasing concentrations of carbon dioxide starves the flame of oxygen. 

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FIG. 3. The force of detachment from excised rabbit intestinal mucosa for directly compressed buccal tablets which contained 40 mg CPM (chlorpheniramine maleate) and 0, 2, 12, 22, and 32 mg Hakea applied to the mucosa with a force of 5 N (— —), 10 N (—0—), 15 N (—O—), and 20 N (—A—). All data points represent the mean value standard deviation of ten experiments. Lines through mean values are included to illustrate the trend and represent a mathematical fit of the data as well (from Ref. 29). 

Suppose a researcher believes a system behaves according to the model y,- = Po + Pi ii + ll over the domain 0 < jc, < 10. Suggest a set of ten experiments that might be useful in either disproving the researcher s hypothesis or increasing the confidence that the researcher s hypothesis is correct. Give reasons for your chosen design. 

We assume a limited budget that allows resources for only ten experiments. How can these experiments be distributed among factor combinations (design points) and replicates At what levels of pH should the experiments be carried out How can the results be interpreted ... 

What information could be obtained if all ten experiments were carried out at only three levels of pH Three levels of x, (f= 3) provides sufficient factor combinations for being able to fit a three-parameter model, but leaves no degrees of freedom for estimating lack of fit / - p = 3 - 3 = 0. Because one of our objectives was to determine if a parabolic relationship provides an adequate model for the observed rate, we must be able to estimate the variance due to lack of fit of the model the number of factor combinations (levels of x, in this example) must therefore be greater than three. 

For the ten-experiment design with six replicates at the center point. 

The parameter estimates with this design will be more precise than they would be with either a five-experiment design (see Equation 11.8) or, with the exception of the estimate of PJ, a ten-experiment design with six replicates at the center point (see Equation 11.11). We will use as our design here, the allocation represented in Equation 11.12. 

Response Surfaces. 3. Basic Statistics. 4. One Experiment. 5. Two Experiments. 6. Hypothesis Testing. 7. The Variance-Covariance Matrix. 8. Three Experiments. 9. Analysis of Variance (ANOVA) for Linear Models. 10. A Ten-Experiment Example. 11. Approximating a Region of a Multifactor Response Surface. 12. Additional Multifactor Concepts and Experimental Designs. Append- ices Matrix Algebra. Critical Values of t. Critical Values of F, a = 0.05. Index. 

In a later paper1 Keiser published a new value for the ratio, based on the mean of ten experiments ... 

In their analyses of sodium chloride in 1905, Richards and Wells 1 purified their materials with extreme care, an example being their application of the centrifuge to the removal of the mother-liquor from sodium chloride after crystallization. Their work involved the determination of the two ratios AgCl NaCl and Ag NaCl. For the experimental details of this classical investigation the original paper should be consulted. In two series of ten experiments each the results were ... 

Fig. 6.5. Time and the value of a hypothetical separation criterion for ten experiments in a Pareto optimality plot experiments I, 2 and 5 are Pareto optimal.

SIMPLEX LATTICE DESIGNS FOR SIX. SEVEN AND TEN EXPERIMENTS AND THREE... 

From the ten experiments, the response surface model was recalculated ... 

RSM yields the maximum amount of information from the minimum amount of work. For example, in the one-variable-at-a-time approach, shown in Fig, 1, ten experiments were run only to find the suboptimum conditions. However, using RSM and thirteen properly designed experiments not only would the true optimum have been found, but also the information necessary to design the process would have been made available. Secondly, since all of the experiments can be run simultaneously, the results could be obtained quickly. This is the power of response surface methodology. 

To make this book even easier to grasp and read, we compiled three important lists to help you in your study of inorganic chemistry. In Chapter 20, we introduce and explain ten common household products. Then, in Chapter 21, you meet ten of the most important Nobel Prizes that were awarded to chemists. Chapter 22 introduces ten instruments and techniques that are commonly found and used in laboratories across the globe. And finally we give you ten experiments that you can try out at home in Chapter 23. Remember, one of the most fun parts of chemistry is doing chemistry, and this chapter gives you some fun experiments to try. 

The last part of this book (Part V and the Part of Tens) gives you some nontechnical information about inorganic chemistry. We start right at home by listing some of the common household products that involve inorganic chemical reactions, or inorganic compounds in Chapter 20. These household items may come in handy if you want to try out any of the ten experiments listed in Chapter 23. 

The repeatability of the experimental data is very good. The means and the coeiBcients of variation from ten experiments with sample 11 are shown in table 4-32... 

The values of the coefficients of friction and the wear rate were determined as the arithmetic means of ten experiments, the mean-square error for the coefficients of friction being 0.003. Korshak et al. (1968). 

In Tables 4-7, the within-laboratory reproducibility standard deviation (sw), the reproducibility limit (Rw), and the relative standard deviation (RSDw), as well as CV derived from Horwitz equation are given for the contamination levels of 0.1 mg/kg, 0.3 mg/kg, 0.5 mg/kg, and 1.0 mg/kg. The results for sw, Rw and RSDw for each individual trichothecene were calculated from six experiments done in duplicates at the contamination level of 0.1 mg/kg and from ten experiments done in duplicates at the other three contamination levels except those for DON and nivalenol at the concentration levels of 0.3 mg/kg and 1.0 mg/kg which were calculated from nine experiments done in duplicates since one result at each of the two contamination levels was eliminated by the Cochran test. The experimental RSDw values were compared to the CV values derived from Horwitz equation. Majority of experimental RSDw values were lower than reference values, only a few exceeded it. However, they were much lower than upper limits for RSDr given in Regulation (EC) No 401/2006 (European Commission, 2006a) which were 40% for DON and 60% for T-2 and HT-2, thus the determined RSDw are considered acceptable. 

Figure 2.16 The calculated standard deviation for an autocorrelation experiment (solid line) where N= 1, Tp = 159 (JLS,/C= 10, =11 KHz and assuming a total measurement time of 30 s using equation 2.33. Also shown is the standard deviation calculated from a repeat of ten experiments given by equation 2.34 (grey squares). Parameters from the weighted fit to the data set for each of the ten curves were approximately the same as in the calculation, for comparison.

The concentration of total urate rose in nine of the ten experiments with an average increment of 0.5 mg%. In the study shown here the urate level of the injectate was 7.6 mg% and of the last sample was 8.9 mg%. Remember, of course, that this is in the forearm. The Increment at the big toe might be less, but on the other hand, it might also be more. -i ... 

Propylamino-bonded silica gel plates were used in a normal phase system, the diluent was hexane, and benzene, chloroform, and tetrahydrofuran were the selected modifiers. Ten experiments were carried out for the eleven dyes of interest and the optimum was located. Issaq and co-workers [28] used the technique for separation of four naphthalene derivatives on a Cig plate. This method has been used as well for optimization of the separation of a sample of unknown composition [29], which is discussed in the Section III.C. 

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