AP Chemistry Flashcards: Introduction For Reactions

What this deck covers

This deck focuses on Introduction For Reactions, giving you a quick way to review the definitions, rules, and examples that matter most for AP Chemistry.

How to use these flashcards

Work through these flashcards in short sessions. Try to answer each prompt before flipping the card, then revisit any cards you miss until the explanation feels automatic.

Flashcard 1: What does a large $K$ value indicate about a reaction?

Answer: The reaction favors the formation of products. Equilibrium lies far to the right toward products.

Flashcard 2: What is the formula for the reaction rate?

Answer: Reaction rate = $\frac{\text{change in concentration}}{\text{time}}$. Measures how fast concentration changes over time.

Flashcard 3: Identify the type of reaction: $2HgO \rightarrow 2Hg + O_2$

Answer: Decomposition reaction. One compound breaks down into two or more simpler substances.

Flashcard 4: What is the definition of a chemical reaction?

Answer: A process where substances convert into different substances. This defines the fundamental nature of chemical change.

Flashcard 5: What effect does a catalyst have on equilibrium?

Answer: A catalyst does not affect the position of equilibrium. Only affects the rate of reaching equilibrium, not position.

Flashcard 6: What is chemical equilibrium?

Answer: A state where the rates of the forward and reverse reactions are equal. Forward and reverse reaction rates are equal at equilibrium.

Flashcard 7: What does a small $K$ value indicate about a reaction?

Answer: The reaction favors the formation of reactants. Equilibrium lies far to the left toward reactants.

Flashcard 8: What is a balanced chemical equation?

Answer: An equation where the number of each type of atom is equal on both sides. Follows the law of conservation of mass.

Flashcard 9: Which option represents an endothermic reaction?

Answer: A reaction that absorbs energy from its surroundings. Products have higher energy than reactants.

Flashcard 10: What is a coefficient in a chemical equation?

Answer: A number in front of a formula indicating the number of molecules. Changes coefficients to balance equations without altering formulas.

Flashcard 11: What is chemical equilibrium?

Answer: A state where the rates of the forward and reverse reactions are equal. Forward and reverse reaction rates are equal at equilibrium.

Flashcard 12: What is the definition of a chemical reaction?

Answer: A process where substances convert into different substances. This defines the fundamental nature of chemical change.

Flashcard 13: Identify the type of reaction: $2HgO \rightarrow 2Hg + O_2$

Answer: Decomposition reaction. One compound breaks down into two or more simpler substances.

Flashcard 14: Define reduction in terms of electron transfer.

Answer: Gain of electrons. Oxidation number decreases when electrons are gained.

Flashcard 15: What effect does a catalyst have on equilibrium?

Answer: A catalyst does not affect the position of equilibrium. Only affects the rate of reaching equilibrium, not position.

Flashcard 16: Identify the type of reaction: $NaCl + AgNO_3 \rightarrow NaNO_3 + AgCl$

Answer: Double displacement reaction. Two ionic compounds exchange ions to form new compounds.

Flashcard 17: Which option represents an exothermic reaction?

Answer: A reaction that releases energy, usually in the form of heat. Products have lower energy than reactants.

Flashcard 18: What is meant by the term 'reactant'?

Answer: A starting substance in a chemical reaction. These are the initial materials that undergo transformation.

Flashcard 19: What is an intermediate in a reaction mechanism?

Answer: A species that is formed and consumed during the reaction sequence. Temporary species that appears in mechanism but not overall equation.

Flashcard 20: Which option represents an exothermic reaction?

Answer: A reaction that releases energy, usually in the form of heat. Products have lower energy than reactants.

Flashcard 21: Identify the symbol for a liquid in chemical equations.

Answer: (l). Indicates the substance is in liquid state.

Flashcard 22: What is chemical equilibrium?

Answer: A state where the rates of the forward and reverse reactions are equal. Forward and reverse reaction rates are equal at equilibrium.

Flashcard 23: What is meant by 'Le Chatelier's Principle'?

Answer: If a system at equilibrium is disturbed, the system will shift to counteract the disturbance. System responds to minimize the effect of external changes.

Flashcard 24: What is a subscript in a chemical formula?

Answer: A number indicating the number of atoms of an element in a molecule. Cannot be changed when balancing chemical equations.

Flashcard 25: Identify the symbol for a solid in chemical equations.

Answer: (s). Shows the substance exists in solid state.

Flashcard 26: Identify the symbol for an aqueous solution in chemical equations.

Answer: (aq). Indicates the substance is dissolved in water.

Flashcard 27: State the law of conservation of mass in reactions.

Answer: Mass is conserved; mass of reactants equals mass of products. Atoms cannot be created or destroyed in chemical reactions.

Flashcard 28: What does a small $K$ value indicate about a reaction?

Answer: The reaction favors the formation of reactants. Equilibrium lies far to the left toward reactants.

Flashcard 29: Which option represents an exothermic reaction?

Answer: A reaction that releases energy, usually in the form of heat. Products have lower energy than reactants.

Flashcard 30: What is a subscript in a chemical formula?

Answer: A number indicating the number of atoms of an element in a molecule. Cannot be changed when balancing chemical equations.

Flashcard 31: Define oxidation in terms of electron transfer.

Answer: Loss of electrons. Oxidation number increases when electrons are lost.

Flashcard 32: Identify the type of reaction: $A + BC \rightarrow AC + B$

Answer: Single displacement reaction. One element replaces another in a compound.

Flashcard 33: What is the definition of a chemical reaction?

Answer: A process where substances convert into different substances. This defines the fundamental nature of chemical change.

Flashcard 34: What does an arrow pointing right signify in a chemical equation?

Answer: Represents the direction of the reaction, from reactants to products. Shows the flow of chemical transformation.

Flashcard 35: What is activation energy in a chemical reaction?

Answer: The minimum energy required to initiate a reaction. Energy barrier that must be overcome for reaction to proceed.

Flashcard 36: What is meant by the term 'reactant'?

Answer: A starting substance in a chemical reaction. These are the initial materials that undergo transformation.

Flashcard 37: What is a coefficient in a chemical equation?

Answer: A number in front of a formula indicating the number of molecules. Changes coefficients to balance equations without altering formulas.

Flashcard 38: Which option represents an endothermic reaction?

Answer: A reaction that absorbs energy from its surroundings. Products have higher energy than reactants.

Flashcard 39: Identify the type of reaction: $NaCl + AgNO_3 \rightarrow NaNO_3 + AgCl$

Answer: Double displacement reaction. Two ionic compounds exchange ions to form new compounds.

Flashcard 40: What does an arrow pointing right signify in a chemical equation?

Answer: Represents the direction of the reaction, from reactants to products. Shows the flow of chemical transformation.

Flashcard 41: What is dynamic equilibrium?

Answer: A state where reactants and products are formed at the same rate. Concentrations remain constant but reactions continue occurring.

Flashcard 42: What is meant by the term 'product' in a reaction?

Answer: A substance formed as a result of a chemical reaction. These are the new substances created from reactants.

Flashcard 43: Identify the symbol for a gas in chemical equations.

Answer: (g). Shows the substance exists in gaseous state.

Flashcard 44: What does a large $K$ value indicate about a reaction?

Answer: The reaction favors the formation of products. Equilibrium lies far to the right toward products.

Flashcard 45: Identify the type of reaction: $A + BC \rightarrow AC + B$

Answer: Single displacement reaction. One element replaces another in a compound.

Flashcard 46: What is a balanced chemical equation?

Answer: An equation where the number of each type of atom is equal on both sides. Follows the law of conservation of mass.

Flashcard 47: Identify the type of reaction: $2H_2 + O_2 \rightarrow 2H_2O$

Answer: Combustion reaction. Hydrocarbon combines with oxygen to form water and carbon dioxide.

Flashcard 48: What is meant by the term 'product' in a reaction?

Answer: A substance formed as a result of a chemical reaction. These are the new substances created from reactants.

Flashcard 49: Identify the type of reaction: $A + BC \rightarrow AC + B$

Answer: Single displacement reaction. One element replaces another in a compound.

Flashcard 50: Which factor increases the rate of a reaction?

Answer: Increasing temperature, concentration, surface area, or adding a catalyst. These factors increase molecular collisions and energy.

Flashcard 51: Identify the oxidizing agent in a redox reaction.

Answer: The substance that gains electrons. It causes reduction by accepting electrons from another species.

Flashcard 52: Which factor increases the rate of a reaction?

Answer: Increasing temperature, concentration, surface area, or adding a catalyst. These factors increase molecular collisions and energy.

Flashcard 53: What is an intermediate in a reaction mechanism?

Answer: A species that is formed and consumed during the reaction sequence. Temporary species that appears in mechanism but not overall equation.

Flashcard 54: What does a large $K$ value indicate about a reaction?

Answer: The reaction favors the formation of products. Equilibrium lies far to the right toward products.

Flashcard 55: What does a small $K$ value indicate about a reaction?

Answer: The reaction favors the formation of reactants. Equilibrium lies far to the left toward reactants.

Flashcard 56: Identify the symbol for a gas in chemical equations.

Answer: (g). Shows the substance exists in gaseous state.

Flashcard 57: What is meant by the term 'product' in a reaction?

Answer: A substance formed as a result of a chemical reaction. These are the new substances created from reactants.

Flashcard 58: Identify the symbol for a liquid in chemical equations.

Answer: (l). Indicates the substance is in liquid state.

Flashcard 59: What is dynamic equilibrium?

Answer: A state where reactants and products are formed at the same rate. Concentrations remain constant but reactions continue occurring.

Flashcard 60: Which factor affects the position of equilibrium?

Answer: Changes in concentration, temperature, or pressure. These external changes shift equilibrium to relieve stress.

Flashcard 61: Identify the type of reaction: $NaCl + AgNO_3 \rightarrow NaNO_3 + AgCl$

Answer: Double displacement reaction. Two ionic compounds exchange ions to form new compounds.

Flashcard 62: Identify the type of reaction: $2H_2 + O_2 \rightarrow 2H_2O$

Answer: Combustion reaction. Hydrocarbon combines with oxygen to form water and carbon dioxide.

Flashcard 63: State the collision theory of chemical reactions.

Answer: Reactions occur when particles collide with sufficient energy and proper orientation. Explains why reaction rate depends on concentration and temperature.

Flashcard 64: What is meant by the term 'reactant'?

Answer: A starting substance in a chemical reaction. These are the initial materials that undergo transformation.

Flashcard 65: What is a balanced chemical equation?

Answer: An equation where the number of each type of atom is equal on both sides. Follows the law of conservation of mass.

Flashcard 66: Define oxidation in terms of electron transfer.

Answer: Loss of electrons. Oxidation number increases when electrons are lost.

Flashcard 67: What is meant by 'reaction mechanism'?

Answer: The step-by-step sequence of elementary reactions by which a chemical change occurs. Shows the detailed pathway from reactants to products.

Flashcard 68: Identify the oxidizing agent in a redox reaction.

Answer: The substance that gains electrons. It causes reduction by accepting electrons from another species.

Flashcard 69: What is an oxidation-reduction (redox) reaction?

Answer: A reaction where electrons are transferred between substances. Involves changes in oxidation states of elements.

Flashcard 70: Identify the symbol for a liquid in chemical equations.

Answer: (l). Indicates the substance is in liquid state.

Flashcard 71: What is an intermediate in a reaction mechanism?

Answer: A species that is formed and consumed during the reaction sequence. Temporary species that appears in mechanism but not overall equation.

Flashcard 72: State the law of conservation of mass in reactions.

Answer: Mass is conserved; mass of reactants equals mass of products. Atoms cannot be created or destroyed in chemical reactions.

Flashcard 73: What is the formula for the reaction rate?

Answer: Reaction rate = $\frac{\text{change in concentration}}{\text{time}}$. Measures how fast concentration changes over time.

Flashcard 74: What does an arrow pointing right signify in a chemical equation?

Answer: Represents the direction of the reaction, from reactants to products. Shows the flow of chemical transformation.

Flashcard 75: Identify the symbol for a gas in chemical equations.

Answer: (g). Shows the substance exists in gaseous state.

Flashcard 76: Identify the type of reaction: $A + BC \rightarrow AC + B$

Answer: Single displacement reaction. One element replaces another in a compound.

Flashcard 77: Identify the reducing agent in a redox reaction.

Answer: The substance that loses electrons. It causes oxidation by donating electrons to another species.

Flashcard 78: Identify the symbol for an aqueous solution in chemical equations.

Answer: (aq). Indicates the substance is dissolved in water.

Flashcard 79: What is dynamic equilibrium?

Answer: A state where reactants and products are formed at the same rate. Concentrations remain constant but reactions continue occurring.

Flashcard 80: Which factor increases the rate of a reaction?

Answer: Increasing temperature, concentration, surface area, or adding a catalyst. These factors increase molecular collisions and energy.

Flashcard 81: Identify the symbol for an aqueous solution in chemical equations.

Answer: (aq). Indicates the substance is dissolved in water.

Flashcard 82: What is a coefficient in a chemical equation?

Answer: A number in front of a formula indicating the number of molecules. Changes coefficients to balance equations without altering formulas.

Flashcard 83: Identify the symbol for a liquid in chemical equations.

Answer: (l). Indicates the substance is in liquid state.

Flashcard 84: Define the equilibrium constant, $K$.

Answer: A ratio of product concentrations to reactant concentrations at equilibrium. Expressed as $K = \frac{[products]}{[reactants]}$ at constant temperature.

Flashcard 85: Identify the reducing agent in a redox reaction.

Answer: The substance that loses electrons. It causes oxidation by donating electrons to another species.

Flashcard 86: What is activation energy in a chemical reaction?

Answer: The minimum energy required to initiate a reaction. Energy barrier that must be overcome for reaction to proceed.

Flashcard 87: What does an arrow pointing right signify in a chemical equation?

Answer: Represents the direction of the reaction, from reactants to products. Shows the flow of chemical transformation.

Flashcard 88: Define the equilibrium constant, $K$.

Answer: A ratio of product concentrations to reactant concentrations at equilibrium. Expressed as $K = \frac{[products]}{[reactants]}$ at constant temperature.

Flashcard 89: Which factor affects the position of equilibrium?

Answer: Changes in concentration, temperature, or pressure. These external changes shift equilibrium to relieve stress.

Flashcard 90: What is meant by 'reaction mechanism'?

Answer: The step-by-step sequence of elementary reactions by which a chemical change occurs. Shows the detailed pathway from reactants to products.

Flashcard 91: Which option represents an endothermic reaction?

Answer: A reaction that absorbs energy from its surroundings. Products have higher energy than reactants.

Flashcard 92: What is meant by 'Le Chatelier's Principle'?

Answer: If a system at equilibrium is disturbed, the system will shift to counteract the disturbance. System responds to minimize the effect of external changes.

Flashcard 93: Which option represents an exothermic reaction?

Answer: A reaction that releases energy, usually in the form of heat. Products have lower energy than reactants.

Flashcard 94: What is meant by the term 'product' in a reaction?

Answer: A substance formed as a result of a chemical reaction. These are the new substances created from reactants.

Flashcard 95: Identify the reducing agent in a redox reaction.

Answer: The substance that loses electrons. It causes oxidation by donating electrons to another species.

Flashcard 96: State the role of a catalyst in a chemical reaction.

Answer: A substance that increases reaction rate without being consumed. Lowers activation energy by providing alternative pathway.

Flashcard 97: What does a small $K$ value indicate about a reaction?

Answer: The reaction favors the formation of reactants. Equilibrium lies far to the left toward reactants.

Flashcard 98: Identify the oxidizing agent in a redox reaction.

Answer: The substance that gains electrons. It causes reduction by accepting electrons from another species.

Flashcard 99: What does a large $K$ value indicate about a reaction?

Answer: The reaction favors the formation of products. Equilibrium lies far to the right toward products.

Flashcard 100: Which factor affects the position of equilibrium?

Answer: Changes in concentration, temperature, or pressure. These external changes shift equilibrium to relieve stress.