Factors affecting reaction rate reactant temperature

Other factors that affect reaction rates are temperature and catalysts. Heating a reaction generally increases the rate at which the reaction occurs by providing the reactant... 

In Lab 17.1, you learned about the effect of temperature and concentration on reaction rate. Another factor that affects reaction rate is the amount of surface area of the reactants. If a chemical reaction is to take place, the molecules of reactants must collide. Changing the amount of surface area modifies the rate of collision, and, thus, the rate of reaction. If surface area increases, collision frequency increases. If surface area decreases, so does the number of collisions. In this lab, you will examine the effect of surface area on rate of reaction. You will also determine how a combination of factors can affect reaction rate. 

We explore four variables that affect reaction rates concentration, physical states of reactants, temperature, and presence of catalysts. These factors can be understood in terms of the collisions among reactant molecules that lead to reaction. 

Four factors affect the rates of all reactions (1) the nature of the reactants, (2) reactant concentrations, (3) reactant temperature, and (4) the presence of catalysts. 

The five factors that can affect the rates of chemical reaction are the nature of the reactants, the temperature, the concentration of the reactants, the physical state of the reactants, and the presence of a catalyst. 

How do factors such as concentration, temperature, a different reactant, and surface area affect the rate of this reaction ... 

In this section, you learned how to relate the rate of a chemical reaction to the concentrations of the reactants using the rate law. You classified reactions based on their reaction order. You determined the rate law equation from empirical data. Then you learned about the half-life of a first-order reaction. As you worked through sections 6.1 and 6.2, you may have wondered why factors such as concentration and temperature affect the rates of chemical reactions. In the following section, you will learn about some theories that have been developed to explain the effects of these factors. 

Based on experimental results and a model describing the kinetics of the system, it has been found that the temperature has the strongest influence on the performance of the system as it affects both the kinetics of esterification and of pervaporation. The rate of reaction increases with temperature according to Arrhenius law, whereas an increased temperature accelerates the pervaporation process also. Consequently, the water content decreases much faster at a higher temperature. The second important parameter is the initial molar ratio of the reactants involved. It has to be noted, however, that a deviation in the initial molar ratio from the stoichiometric value requires a rather expensive separation step to recover the unreacted component afterwards. The third factor is the ratio of membrane area to reaction volume, at least in the case of a batch reactor. For continuous opera-... 

In Equation 3.1, the suffix i usually designates a reaction product. Ihe rate r,-is negative, in case i is a reactant. Several factors, such as temperature, pressure, the concentrations of the reactants, and also the existence of a catalyst affect the rate of a chemical reaction. In some cases, what appears to be one reaction may in fact involve several reaction steps in series or in parallel, one of which may be rate limiting. 

The idea of equilibrium hinges on the concept of reaction rates. In chemistry rate refers to how much something changes in a unit of time. The something that changes is the concentration of a reactant or a product, usually expressed as molarity. The unit of time is generally the second, although any unit of time can be used. Sometimes it is desirable to manipulate the rate of a reaction in order to speed it up or slow it down. The factors that affect the rate of a reaction are temperature, concentration, surface area, and the use of a catalyst. 

Any of six factors can affect the rate (1) the nature of the reactants, (2) the temperature, (3) the presence of a catalyst, (4) the concentration of reactants in solution, (5) the pressure of gaseous reactants, and (6) the state of subdivision of solid reactants. For a reaction to occur, the atoms, molecules, or ions must come into contact with one another with enough energy to rearrange chemical bonds in some way. Increased concentration, gas pressure, or surface area of a solid tends to get the particles to collide more frequently, and increased temperature tends to get them to collide more frequently and with greater energy to accomplish more effective collisions. Catalysts work in very many different ways. 

The equilibrium constant expression is in the same form as the ratio in the Nemst equation (Chapter 17). The square brackets mean the molarity of the substance they enclose, and the constant K is called the equilibrium constant. The entire equation is known as the equilibrium constant expression. No matter what the initial concentrations of reactants or products, the ratio of the concentrations at equilibrium will be equal to the constant K. The value of K depends only on the specific chemical equation and on the temperature. It does not depend on any of the other factors that can affect the rate of a reaction. For example, if different quantities of the same reactants and products are introduced into different reaction vessels, they will react with one another until, at equilibrium, the same ratio of concentrations, each raised to the appropriate power, is established. 

The majority of the degradation reactions of pharmaceuticals take place at finite rates and are chemical in nature. Solvent, concentration of reactants, temperature, pH of the medium, radiation energy, and the presence of catalysts are important factors that affect these reactions. The order of the reaction is characterized by the manner in which the reaction rate depends on the reactant concentration. The degradation of most pharmaceuticals is classified as zero order, first order, or pseudo-first order, although the compounds may degrade by complicated mechanisms, and the true expression may be of higher order or be complex and noninteger. 

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