Molecules balloon models

A balloon model of the electron clouds repelling each other in a molecule of methane. 

The balloon model represents the clouds of bonding electrons on either side of the carbon atom. A linear molecule results because of repulsion between the two clouds. ... 

If they are available, use inflated balloons or molecule modeling kits to construct each of the arrangements in Figure 4.11. How do these models compare with your bubble models ... 

Lennemas et al. have developed a method for measuring human effective permeability (H-Peff) using a regional intestinal perfusion technique. In this method, a perfusion apparatus consisting of a multichannel tube with two inflatable balloons (10 cm apart) is swallowed by the patient and eventually located in the proximal jejunum. Dilute solutions of the test drag are introduced at the inlet located at the center of the 10 cm section, and the loss of drag is determined from the concentration in the outlet intestinal perfusate. In such a fashion, the H-Peff for 22 carefully selected drug molecules has been determined and a theoretical model of H-Peff has been developed. " The small size of the published H-Peff database is most likely due to the expense of the human measurement. 

Four balloons, inflated equally and held together at a central point, arrange themselves in a tetrahedral shape. This is the most space-efficient arrangement for four things about a center point. In this model, the balloons represent the four electron pairs of the water molecule. ... 

An ideal gas is simply a model of the way that particles (molecules or atoms) behave at the microscopic level. The behavior of the individual particles can be inferred from the macroscopic behavior of samples of real gases. We can easily measure temperature, volume, pressure, and quantity (mass) of real gases. Similarly, when we systematically change one of these properties, we can determine the effect on each of the others. For example, putting more molecules in a balloon (the act of blowing up a balloon) causes its volume to increase in a predictable way. In fact, careful measurements show a direct proportionality between the quantity of molecules and the volume of the balloon, an observation made by Amadeo Avo-gadro more than 200 years ago. 

Tlie repertoue of active molecules has extended to include DNA itself. The therapeutic potential of DNA enzymes was demonstrated with a stretch designed to bind to and cleave the RNA made by a damage-sensing gene called Egr-1, which appears to keep ballooned arteries from closing up in rate models of heart disease. 

Construct models of molecules by using inflated balloons. 

Push two of the round balloons together so that the tape loop on each balloon sticks to the other balloon, as shown in Figure A. This is a model of the hydrogen molecule, H2. Describe the shape of the model in Data Table 1. 

We can use the example of the balloons to model the shapes that methane (CH4), ammonia (NH3), and water (HgO) assume. As you look at each of these molecules in Figures 1.6-1.8, take note of (1) the number of regions of electron density shown by the Lewis structure, (2) the geometry that is required to maximize the separation of these regions of electron density, and (3) the names of the shapes that result from this treatment using VSEPR. 

Figure 8.6 compares the vertical profiles of the O3 desfruction rates by each of the Ox, HOx, NOx, ClOx and BrOx cycles, calculated by a model considering all the reactions mentioned in Sects. 8.1, 8.2 and in this section, with those values calculated based on the observed values of radicals by a balloon (Osterman et al. 1997). As shown in the figure, these gas phase chain cycles cause large O3 destruction above 30 km in the upper stratosphere, and in the middle and lower stratosphere below 30 km the dissipation rate is less than 2 x 10 molecules cm s . Figure 8.7 shows the relative contribution of each cycle to the O3 destruction (Osterman et al. 1997). As shown in Fig. 8.7, the contribution of HOx is the most important in the upper stratosphere above 40 km and also in the lower stratosphere... 

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