Writing and Predicting Chemical Reactions

Question 1 of Section II (also known as Part A) of the AP chemistry exam is always a question on writing reactions. The directions for this question follow. 

You may NOT use a calculator for this section of the exam. You will be given 10 minutes to answer FIVE of the eight options in this part. (Answers to more than five options will not be scored.) 

Give the formulas to show the reactants and the products for FIVE of the following chemical reactions. Each of the reactions occurs in aqueous solution unless otherwise indicated. Represent substances in solution as ions if the substance is extensively ionized. Omit formulas for any ions or molecules that are unchanged by the reaction. In all cases a reaction occurs. You need not balance. 

Example A strip of magnesium is added to a solution of silver nitrate. 

Reactions of Alkali Metals and Alkaline Earth Metals 

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Every once in a while you may run into an organic chemistry problem in Section II, on writing equations. An example is Write an equation that describes burning methanol in air. You would need to know the chemical formula and structural formula of methanol in order to do this problem. Writing organic reactions is covered in more detail in the chapter entitled Writing and Predicting Chemical Reactions. ... 

The roman numeral in each answer refers to the section in the chapter entitled Writing and Predicting Chemical Reactions. For example, I is found on page 216. 

The basic principles discussed at the beginning of Chapter 17 (in connection with the construction of simple electrochemical cells) are exactly the ones used to write and balance chemical equations for electron-transfer reactions. These principles also enable you to predict whether or not a given electron-transfer reaction will actually take place. 

In an alternate experiment, the R2 resin is reacted with epichlorohydrin and the oxirane ring hydrolyzed using NH3. Write down the chemical reactions and predict their capacity. The resultant resin could be regenerated repeatedly. 

Predict what will happen when the following pairs of substances are allowed to react. Write a balanced chemical equation for each reaction. When the reaction involves ions, write a net ionic equation. Identify each reaction as precipitation, as acid-base, or as redox, (a) AgN03(a q) and NaCl(a q) (b)... 

It is not difficult to write a number of chemical equations to represent physical, thermal, and chemical reactions taking place in a gasification vessel. In theory, gasification processes can be designed so that heat release (exothermic reactions) balances the heat required by endothermic reactions. But in practice many of the above physical, thermal, and chemical reactions may take place simultaneously, making a precise prediction of the quantity and quality or composition of product gas somewhat difficult. 

Predict whether each of the following single displacement reactions will occur. If so, write a balanced chemical equation, a balanced net ionic equation, and two balanced half-reactions. Include the physical states of the reactants and products in each case. 

Selim Senkan is noted for his work in environmental engineering, and particularly for his work in the reaction rates of chlorinated hydrocarbons. He writes in Detailed Chemical Kinetic Mechanisms on the impact of efficient numerical algorithms and computational quantum mechanics on the prediction of reaction mechanisms and rates. 

Write a balanced chemical equation for each double displacement reaction. Write NR if you predict that no reaction will occur. Note that K+, Na+, and Li+ ions form soluble compounds with all anions. All nitrate compounds are soluble. Sulfate compounds with Ca2+,... 

Predict the products of each reaction. Then write a balanced chemical equation, and state which class the reaction belongs to. 

Write the chemical formulas for calcium chloride and ammonium sulfate. Predict what kind of reaction will occur between them. Write a balanced chemical equation to show the reaction. Ionic compounds containing the ammonium ion are soluble. Ammonium sulfate is soluble, but barium chloride is not. 

In Chapter 7, we learned how to do nnmerical calculations for compounds, using their formulas as a basis. This chapter lays the foundation for doing similar calculations for chemical reactions, using the balanced equation as a basis. The chemical equation is introduced in Section 8.1, and methods for balancing equations are presented in Section 8.2. To write equations, we must often be able to predict the products of a reaction from a knowledge of the properties of the reactants. Section 8.3 shows how to classify chemical reactions into types to predict the products of thousands of reactions. An important type of reaction— the acid-base reaction— is discussed in Section 8.4. 

Predict the products that will result when these reactants combine and write a balanced chemical equation for each reaction. 

Table 9.4 summarizes the various types of chemical reactions. Use the table to help you organize the reactions, so that you can identify each and predict its products. For example, how would you determine what type of reaction occurs when solid calcium oxide and carbon dioxide gas react to produce solid calcium carbonate First, write the chemical equation. 

Predict which of the two compounds, methane gas (GEI4) or methanal vapor (GH2O), has the greater molar enthalpy of combustion. Explain your answer. (Hint Write and compare the balanced chemical equations for the two combustion reactions.)... 

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