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32 Cards in this Set
- Front
- Back
Define reaction rate
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rate of reaction, is a measure of how fast a reaction occurs
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What are the 4 conditions that affect the rate of reaction?
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temperature, reactant concentration, surface area, and the presence of a catalyst
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How does temperature affect the rate of the reaction?
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higher temperatures generally cause reactions to occur faster
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How does the concentration affect the rate of the reaction?
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Increasing the concentration of a reactant generally increases the reaction rate
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How does the surface area affect the rate of the reaction?
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Ifthe reactant is a solid, increasing its surface area also increases reaction rate.
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Explain how when a metal is in granular form, it affects the reaction rate.
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Metals in their granular form have greater surface area and react more quickly with air than large pieces of metal
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What does the collision theory state?
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states that in order for a reaction to occur, reactant molecules must collide in the proper orientation and with sufficient energy
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What is required for a collision to happen and form a product?
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Must have sufficient energy and must collide in the right place
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If two molecules collide with the proper orientation, will the reaction always occur? Why or Why not?
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No, the molecules must also have a sufficient amount of energy
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Why does the rate of chemical reactions vary so widely?
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Different reactions occur at different rates because the amount of energy required to break bonds in the reactant molecules is different
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What must reactants overcome before they can change to products?
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Reactants must overcome an energy barrier before they can change
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What is the activation energy?
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The minimum amount of energy needed to overcome this energy barrier
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The (lower/higher) the activation energy the faster the reaction/
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lower
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Reactant molecules that collide with the proper orientation and sufficient energy form what?
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An activated complex
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What is an activated complex?
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a short-lived, unstable, high-energy chemical species that must be achieved before products can form
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How can you tell what the activated complex is?
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Designated by a chemical formula in brackets with a superscript double dagger
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Which is faster, a reaction with large activation energies or a reaction with small activation energies
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Reactions with large activation energies tend to be slow and reactions with small activation energies tend to be fast
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What 3 conditions most oft4n affect reaction rates?
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Changes in concentration, surface area, and temperature
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How does the concentration affect the rat of the reaction?
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A reaction may go faster when the concentration of one or more of the reactants increases
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How does the surface area affect the rate of the reaction?
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Increasing the surface area increases the number of atoms that are exposed so that they can collide with other reactions
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Why does the reaction proceed more rapidly at higher temps?
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Because when the temperature inc., the kinetic energy inc., which causes more collisions, which causes the reaction rate to inc.
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How does the increase in kinetic energy cause the reaction rate to increase?
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(1) increases the collision rate (2) increases the fraction of collisions that are effective
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What is a catalyst?
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something that alters the pathway in which a reaction occurs without itself being consumed in the reaction
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How does a catalyst increase the rate of a reaction?
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With lower activation energy, a greater fraction of reactants can achieve the new minimum energy requirement, and the reaction rate increases. The new reaction pathway is a lower-energy pathway with lower activation energy.
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Define enzyme
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a molecule that catalyzes specific reactions within living organisms
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What do enzymes do?
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catalyze all the processes necessary for the proper functioning of the human body
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What are active sites and substrates and how do they correspond?
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a depression or hole that is unique to an enzyme and allows it to interact with only one specific kind of reactant molecule (substrate)
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What is shown in the net equation?
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only the reactants and products
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Define chemical equilibrium
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a state reached by a chemical reaction where there is no change in the concentrations of reactants and products
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When is chemical equilibrium established?
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When a single reaction occurs in which reactants are converted to products, and these products are converted back to reactants by the reverse process at an equal rate
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What happens once a reaction reaches equilibrium?
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The forward reaction continues to occur, but the reverse reaction also occurs at the same rate
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How do you represent a state of equilibrium>
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represented by using an equilibrium arrow (arrow pointing both direction, half arrow)
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