Universiti Pendidikan Sultan Idris Tku 3032: Ict In Chemistry Assignment:

UNIVERSITI PENDIDIKAN SULTAN IDRIS TKU 3032: ICT IN CHEMISTRY ASSIGNMENT: SIMULATION “CHEMICAL REACTIONS: TEMPERATURE” PREPARED BY: 1. NOR RAFIAH BINTI HUSSIN (D20081032374) 2. NORLELA BINTI MOHAMMAD (D20081032375) LECTURER’S NAME: MADAM ASMAYATI BINTI YAHAYA CLASS: THURSDAY (1.00P.M UNTIL 4.00P.M)

CHEMICAL KINETICS Reaction Rates Chemical kinetics is the study of the speed with which a chemical reaction occurs and the factors that affect this speed. This information is especially useful for determining how a reaction occurs. What is meant by the speed of a reaction? The speed of a reaction is the rate at which the concentrations of reactants and products change. Consider the following hypothetical example. The letters A, B, and C represent chemical species (in this context, the letters do not represent elements). Suppose the following imaginary reaction occurs: A+2B → 3C Factor that affect the rate of reaction: Temperature: Usually conducting a reaction at a higher temperature delivers more energy into the system and increases the reaction rate by causing more collisions between particles, as explained by collision theory. However, the main reason that temperature increases the rate of reaction is that more of the colliding particles will have the necessary activation energy resulting in more successful collisions (when bonds are formed between reactants). Usually, an increase in temperature is accompanied by an increase in the reaction rate. Temperature is a measure of the kinetic energy of a system, so higher temperature implies higher average kinetic energy of molecules and more collisions per unit time. A general rule of thumb for most (not all) chemical reactions is that the rate at which the reaction proceeds will approximately double for each 10°C increase in temperature. Once the temperature reaches a certain point, some of the chemical species may be altered (e.g., denaturing of proteins) and the chemical reaction will slow or stop.

ENGAGE You are given the pictures as shown below:

1. What do you observe from the picture? 2. How does the burning develop? 3. How the temperature effect the rate of the reactions?

EMPOWER STEPS 1.Collisions between molecules will be more violent at higher temperatures. 2. The higher temperatures mean higher velocities. This means there will be less time between collisions. 3. The frequency of collisions will increase. The increased number of collisions and the greater violence of collisions results in more effective collisions. 4. The rate for the reaction increases. Reaction rates are roughly doubled when the temperature increases by 10 degrees Kelvin. This means the rate can be quadrupled if the temperature is raised by 20 degrees Kelvin. 5. By increasing the temperature, it will increase the rate of the reactions and by lowering the temperature, it will decrease the rate of the temperature. 6. Log on the web side and observe the animation to answer the question.

Questions: 1. 2. 3.

If the temperature of a chemical reaction time does what? Is temperature change a good indicator of a chemical reaction and why? Can the temperature change during a chemical reaction?

Answers 1.

It depends if the reaction is endothermic (requires heat/energy) or is exothermic (requires no heat/energy and produces heat/energy). In general, most reactions are endothermic and require some amount of energy to 'go' and hence, an increase in temperature will increase the rate of reaction. However, in exothermic reactions, introducing heat can halt the reaction as well as reverse it, if said reaction is reversible.

2.

Yes. It takes energy to form new chemical bonds. When a reaction involves breaking bonds than bond making, energy required is often absorbed from the surroundings, making them cooler. (endothermic) When a reaction involve bondmaking than bond-breaking, the excess energy is released (in form of heat), making the surroundings hotter (exothermic). No because not all reactions have a change in enthalpy (heat). The reactions can be either enthalpy driven or entropy driven, meaning they can be instead drove by entropy(disorder) and also meaning no change in temperature.

3.

Yes. It can change during the chemical reaction due to the another factors that effect the rate of the chemical reactions.

ENHANCE

Questions

1. How a temperature effect the rate of chemical reactions? 2. How did high temperature process ultilizing fluid-wall reactors?

Answers: 1. Heat is a very commonly used catalyst that is used to speed up chemical reactions. When more temperature, or heat, is added to a chemical reaction, then the chemical reaction would occur much more quickly than had it just been left there to react on its own. The velocities of the most chemical reactions increases with the rise of temperature. The temperature affects the number and the energy of collisions. The influence of the temperature on the number of molecule collisions could be shown by the model. 2. A high temperature chemical reaction process in which mineral ores or inorganic compounds are reduced to a lower valence state with hydrogen, carbon, synthesis gas, or other reducing agent can be conducted in fluid-wall reactors by a process which includes the steps of (a) generating an annular envelope of an inert fluid which is substantially transparent to radiation within a shell of a refractory material which reflects radiation; the volume enclosed by the shell constituting a black body cavity, the envelope having substantial axial length and the interior of the envelope defining a reaction chamber; (b) passing at least one reactant into the black body cavity and through the reaction chamber along a predetermined path substantially coincident with the longitudinal axis of the envelope, the reactants being confined within the reaction chamber; and (c) directing high intensity radiant energy into the reaction chamber to coincide with at least a portion of the predetermined path of the reactants, sufficient radiant energy being absorbed within the reaction chamber to raise the temperature of the reactants to a level required to initiate and sustain the desired chemical reaction. .