Word equations

In words, equation (Al.6.89) is saying that the second-order wavefunction is obtained by propagating the initial wavefunction on the ground-state surface until time t", at which time it is excited up to the excited state, upon which it evolves until it is returned to the ground state at time t, where it propagates until time t. NRT stands for non-resonant tenn it is obtained by and cOj -f-> -cOg, and its physical interpretation is... 

Another key requirement of chemical equations (when presented in formulae, see below for consideration of word equations), is that they should be balanced . This is considered further below, and relates to conservations that are expected during chemical processes (of matter, charge, energy). 

Both of these forms of representation are symbohc although words are more familiar symbols to students. Both of these forms present difficulties to learners. Although word equations may seem a more direct way for novices to represent chemical reactions, they may sometimes make more demands on learners. So, for example in completing equations, non-systematic names - such as ammonia - may not provide strong clues to the elements present, and there is a need to learn, recall and apply such rules as -ate implies oxygen present, etc. 

In chemistry we usually indicate the energetics of equations separately from the equation itself (as in Example 9 in Table 4.1), but if energy is included as a term, especially in a word equation, this can undermine the sigiuficant distinction between what is happening in a chemical reaction in terms of matter and energy. 

Some tasks in the Test of Gained Knowledge required students to connect observations about the macro course of chemical reactions with their notations in the submicro and/or symbolic types of representation. The results indicate that most students were able to rearticulate the information about reactants and products of a chemical reaction from the textual description of chemical reaction into the form of word chemical equation (textual description of macros word equation of macro Task 8.2, f(o/ )=89.82% Task 9.1, f(o/ )=87.61%). This action corresponds to the first step in learning to write down chemical equation in the LON approach. It can easily be explained, because teachers described the learning process to be very efficient to this point, as is illustrated below ... 

A chemical reaction is described by means of a shorthand notation called a chemical equation. One or more substances, called reactants or reagents, are allowed to react to form one or more other substances, called products. Instead of using words, equations are written using the formulas for the substances involved. For example, a reaction used to prepared oxygen may be described in words as follows ... 

It is important to realize that statistical-overlap theory is not constrained by the contour of area A, which does not have to be rectangular as in earlier studies (in addition to previous references, see Davis, 1991 Martin, 1991,1992). In other words, Equations 3.2 and 3.3 should apply to the spaces WEG, FAN, and PAR. In this chapter, the number of clusters of randomly distributed circles in such areas is compared to the predictions of Equations 3.2 and 3.3a to assess the relationship between nP and practical peak capacity. Similarly, the number of peak maxima formed by randomly distributed bi-Gaussians in such areas is compared to the predictions of Equations 3.2 and 3.3b, and to Fig. 3.2, to make another assessment. 

The value of AG is only ever negative, as required by a thermodynamically spontaneous process, if the initial pressure / (initial) is greater than the final pressure finai), i.e. the fraction is less than one. In other words, Equation (5.9) shows why AG is negative only if the pressure of the CO2 in the space above the liquid has a pressure that is greater than... 

This means that, if a series of groups of experiments is conducted in such a way that in each experiment f is varied over the useful range and g is constant in each group, but is varied from group to group, then equation (6) described the variation of 1/DPC, with g among the different groups of experiments in other words, equation (6) describes the locus of the apices of the Mayo plots. A set of results of this type is discussed in detail in Example 1. 

Write a word equation for the saponification reaction in this lab. 

Think of the enormous external force required to pull a nucleon out of the nucleus through a distance sufficient to overcome the attractive strong nuclear force, comically represented in Figure 4.28. As per the word equation for work just given, enormous force exerted through a distance means that enormous work is required. This work is energy that has been added to the nucleon. 

To convert the preceding word equations to mathematical statements using symbols, let N represent the number of radioactive nuclei present at time t. Then, using differential calculus, the preceding word equations may be written as... 

Compounds are pure substances which are formed when two or more elements chemically combine together. Water is a simple compound formed from the elements hydrogen and oxygen (Figure 2.6). This combining of the elements can be represented by a word equation ... 

Word equations are a useful way of representing chemical reactions but a better and more useful method is to produce a balanced chemical equation. This type of equation gives the formulae of the reactants and the products as well as showing the relative numbers of each particle involved. 

The word equation to represent the reaction between iron and sulfur is ... 

In the case of magnesium reacting with oxygen, the word equation was ... 

Substances in a mixture have not undergone a chemical reaction and it is possible to separate them provided that there is a suitable difference in their physical properties. If the mixture of iron and sulfur is heated a chemical reaction occurs and a new substance is formed called iron(n) sulfide (Figure 2.11). The word equation for this reaction is ... 

Complete the word equations and write balanced chemical equations for the following soluble salt preparations ... 

The pigment prepared by combustion is carbon. Write a word equation for the chemical change that produced the carbon. 

Write a word equation for the chemical changes that produced the two whiting compounds CaC03 (calcium carbonate), sometimes called precipitated chalk, and Ca(OH)2 (calcium hydroxide), sometimes called slaked lime. After writing the equations, find for each equation the correct classification composition, decomposition, single displacement, or double displacement (see the next subsection, An Artist s Materials and Chemical Change ). 

Students will write a word equation and a chemical equation for the preparation of silver (Ag) crystals. 

Write a word equation for the formation of nylon. Why is this reaction called a condensation reaction ... 

Identify your equation within your composition. Write it as a word equation. 

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