Reaction Rate Chemistry 2023 with verified questions and answers

Reaction Rate time it takes for the reactant to become the product; no chemical reaction is instantaneous For minimum energy required for chemical reaction to occur: must separate (work is done); particles are broken down by dipolar water molecules; ions must fight throught the water to re-combine 3 ways used to study reaction rate: (1) Measure the time it takes for the product to first appear;(colorless to a color) (2) Measure the time it takes for one or both reactants to be used up (will change from one color to a new color); (3) Measure the amount of product formed in a given length of time (need a measurable product such as gas or a solid). K1 - K2S2O8 reaction (the iodine clock) reaction was used to measure the time it takes for the product to first appear KMnO4 - H2C2O4 reaction was used to measure the time it take for one or both reactants to be used up Shell - HCl reaction was used to measure the amount of product formed in a given length of time When potassium permanganate KMnO4 and oxalic acid H2C2O4 have reacted the mixture turns from purple to golden yellow When potassium iodine KI and potassium persulfate K2S2O8 have reacted the solution turns from colorless to a dark blue to blue-black. YOu need to add starch (an indicator) to the mixture. According to the particle model of mater increasing the concentration of a reactant increases the number of particles available for collision. More collision means a faster reaction rate. Concentration is the amont of of solute, matter dissolved, in a given volume of solution. Increasing concentration has no effect on the speed of the matter particles, just the number of particles in a given volume of solution. 3 Methods for changing reaction rates (1) Changing the concentration (2) Changing the temperature (3) Using a catalyst Collision Theory In order for a reaction to occur, particles must collide at the proper angle as well as have propery energy (force of collusion). Energy is neither created nor destroyed ---just changes form. Temperature is the measure of the motion of matter particles KMnO4 - H2O2O4 turned from purple to golden yellow faster faster when heated than when at room temperature Kl - K2S2O8 turned from colorless to dark blue to blue-black in less time when heated than at room temperature Shell - HCl reaction was tested with 4 different temperatures when the HCl was heated, the temperature increased, the amount of gas produced increased When data from the temperature vs amount of product experiment was graphed the relatioship shown was unlimited growth The Particle Model of Matter, increasing temperature increases the motion of matter particles, as the motion increases, the number of particle collisions increase, more particle collisions occuring, the reaction rate is faster. Catalyst is a substance that increases the reaction rate without itself being changed. Experiment where a catalyst was added to hydrogen peroxide when the reaction took place, a transition state took place, solution turned a temporary green color. After reaction was complete, the solution turned back to the original red color of the colbalt. Reaction rate of KMnO4 - H2C2O4 increased when a drop of manganous sulfate MnSO4 was added. The MnSO4 did not react to the KMnO4, the MnSO4 was not a reactant Reaction rate of Kl - K2S2O8 was increased when a copper BB was added. Copper BB did not react the K1, Cooper BB was not a reactant in this reaction MnSO4 had no reaction on the K1 - K2S2O8 reaction rate 3 Characteristics of Catalyst (1) used in small amounts, only a drop of one BB was used; (2) Catalysts are not reactants (3) Catalysts are specific for a few reactants. (MnSO4 works for KMnO4 - H2C2O4 reaction but not K1 - K2S2O8 reaction) Additional Characteristics of Catalyst (1) catalyst may be used for more than one reaction; (BB works well here) (2) Catalysts are found in living or once living matter; (3) Catalysts such as the apple or potatoe (called enzymes) since bubbles formed on its surface. Enzymes Catalysts found in living and once living matter Characteristics of Enzymes made by living things end in -ase sensitive to heat can be regulated living things can literally turn a catalyst on/off Activation energy minimum energy required for a reaction to occur Decomposition reaction rate when a compound heats up the atoms break apart and separate. Exothermic reaction energy is released during the reaction, a net temperature change will increase. It takes more energy for the particles to separate than they release when they re-combine. Endothermic reactions energy that is absorbed during the reaction. Gets colder and if the energy involved is heated, the products woudl appear colder than the reactants.