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Description
Flashcards by jennabarnes12387, updated more than 1 year ago
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Created by jennabarnes12387
over 10 years ago
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| Question | Answer |
| What is the objective of chemical kinetics? | To measure the rate if reactions, how factors like concentration, temperature, and catalysts effect reaction rate, and determine the microscopic steps that transform reactants into products. |
| What are the most important questions concerning chemical reactions? | Can a reaction occur? And how fast does the reaction occur? |
| Why might a reaction seem to not occur on its own accord? | It happens at such a slow rate at that it may seem to not be happening at all |
| What is the definition of the rate of a chemical reaction? | Change in concentration of a product or reactant over a unit of time e.g. Moles/L per s. |
| What is the average rate of reaction for a specific substance over time? | End concentration of a substance minus the initial concentration of a substance divided but the end time minus the initial time |
| What is the rate of disappearance of a substance that decreases in concentration? | Negative change in concentration of A divided by change in time |
| What is the rate of a appearance (a concentration that increases) | Negative change in concentration of B divided by change in time |
| Rate of reaction simplified is? | 1/x X rate of appearance or disappearance of a substance. x is the coefficient for the species in the balanced equation |
| If you are given reaction rate fora full reaction, how to fine the rate of increase or decrease of a specific substance? | 1/the coefficient x rate of appearance/disappearance equation = the given reaction rate. From here just time the given reaction rate by the species coefficient to find the species rate of reaction |
| Why does rate of reaction decreases with time? | Because the rate of reaction depends on the concentration of the reactants. As they react there concentration decreases so the reaction rate will also decrease. |
| How do you calculate the averaged rate of reaction? | The end time - initial time = negative change in concentration divided by change in time |
| How do you find the half life of a first order reaction | T1/2 = 0.693/K |
| How do you find the time it takes for a substance to decompose to a certain percent | First find the value of k for whatever order the reaction is. Then solve for t with the equation natural log of substance concentration at a certain time divided by concentration of a substance at 0 time = -k(t). Remember the concentration ratio is actually equal to what percent is left over. For example if u want to find the time for a substance to decompose 95% u sub statue 0.05 for the concentration ratio |
| How do you calculate the time of reaction for a second order reaction? | 1/final concentration - 1/initial concentration = k x t |
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