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Questions and Answers
Which of the following scenarios best illustrates a double displacement reaction?
Which of the following scenarios best illustrates a double displacement reaction?
- A metal strip corrodes when exposed to oxygen, forming a layer of metal oxide.
- A single compound breaks down into two simpler substances when heated.
- Two clear solutions are mixed, resulting in the formation of a solid precipitate. (correct)
- A more reactive metal replaces a less reactive metal in a compound.
Consider the reaction: $2H_2O(l) + ext{energy}
ightarrow 2H_2(g) + O_2(g)$. Which statement accurately describes this reaction?
Consider the reaction: $2H_2O(l) + ext{energy} ightarrow 2H_2(g) + O_2(g)$. Which statement accurately describes this reaction?
- The reaction is a neutralization reaction forming a salt and water.
- The reaction is a combustion reaction producing carbon dioxide and water.
- The reaction is exothermic because it releases energy as heat.
- The reaction is endothermic because it requires energy input to proceed. (correct)
In a chemical reaction, a catalyst is used. What effect does the catalyst have on the reaction?
In a chemical reaction, a catalyst is used. What effect does the catalyst have on the reaction?
- It increases the energy required for the reaction to begin.
- It gets consumed during the reaction.
- It lowers the activation energy, thus speeding up the reaction. (correct)
- It shifts the equilibrium towards the reactants.
Which of the following correctly identifies the oxidized and reduced species in the reaction: $Zn(s) + Cu^{2+}(aq)
ightarrow Zn^{2+}(aq) + Cu(s)$?
Which of the following correctly identifies the oxidized and reduced species in the reaction: $Zn(s) + Cu^{2+}(aq) ightarrow Zn^{2+}(aq) + Cu(s)$?
How does increasing the concentration of reactants typically affect the rate of a chemical reaction, and why?
How does increasing the concentration of reactants typically affect the rate of a chemical reaction, and why?
Consider the reversible reaction: $N_2(g) + 3H_2(g)
ightleftharpoons 2NH_3(g)$. At equilibrium, what is true about the rates of the forward and reverse reactions?
Consider the reversible reaction: $N_2(g) + 3H_2(g) ightleftharpoons 2NH_3(g)$. At equilibrium, what is true about the rates of the forward and reverse reactions?
Which type of chemical bond is formed through the sharing of electrons between two non-metal atoms?
Which type of chemical bond is formed through the sharing of electrons between two non-metal atoms?
Which of the following actions would likely increase the rate of a reaction between a solid and a liquid?
Which of the following actions would likely increase the rate of a reaction between a solid and a liquid?
Flashcards
Chemical Reaction
Chemical Reaction
Bonds break, atoms rearrange, and new bonds form.
Combination Reaction
Combination Reaction
Two or more reactants combine to form a single product.
Decomposition Reaction
Decomposition Reaction
One reactant breaks down into two or more products.
Combustion Reaction
Combustion Reaction
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Exothermic Reaction
Exothermic Reaction
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Endothermic Reaction
Endothermic Reaction
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Activation Energy
Activation Energy
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Catalyst
Catalyst
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Study Notes
- Chemical reactions involve the breaking of existing chemical bonds, the rearrangement of atoms, and the formation of new bonds.
- A chemical reaction involves two or more substances (reactants) interacting to form new substance(s) (products).
Signs of a Chemical Reaction
- Heat is either released (exothermic) or absorbed (endothermic).
- Change in color.
- Production of a gas, often seen as bubbles.
- Formation of a precipitate, which is a solid that separates from the solution.
Types of Chemical Reactions
- Combination reactions occur when two or more reactants combine to form a single product (A + B → AB).
- Decomposition reactions occur when a single compound breaks down into two or more products (AB → A + B).
- Displacement reactions occur when one element replaces another in a compound (A + BC → AC + B).
- Double displacement reactions occur when two compounds exchange parts (AB + CD → AD + CB).
- Combustion reactions occur when a fuel reacts with oxygen to produce carbon dioxide and water (CH₄ + 2O₂ → CO₂ + 2H₂O).
Endothermic vs. Exothermic Reactions
- Exothermic reactions release heat into the surroundings, such as the burning of fuels.
- Endothermic reactions absorb heat from the surroundings, such as photosynthesis or the reaction in an ice pack.
Acid-Base Reactions
- Acids and bases react to form a salt and water (HCl + NaOH → NaCl + H₂O).
- This is also known as a neutralization reaction.
- Acids donate hydrogen ions (H⁺), while bases donate hydroxide ions (OH⁻).
Activation Energy
- Activation energy is the minimum energy required to start a chemical reaction.
- Even exothermic reactions require activation energy to initiate the process.
Catalysts
- Catalysts speed up reactions by lowering the activation energy needed.
- Catalysts are not consumed in the reaction.
- Enzymes in the body are biological catalysts.
Oxidation-Reduction (Redox) Reactions
- Oxidation involves the loss of electrons.
- Reduction involves the gain of electrons.
- In the example Zn + CuSO₄ → ZnSO₄ + Cu, zinc (Zn) is oxidized and copper (Cu²⁺) is reduced.
Concentration
- Higher concentration of reactants generally leads to a faster reaction rate.
- Increasing the concentration increases the number of particles available to react.
Surface Area
- Increasing the surface area of reactants increases the reaction rate.
- More particles are exposed and available for reaction.
Temperature
- Increasing the temperature generally increases the reaction rate.
- Molecules move faster and collide more frequently with greater energy.
Collision Theory
- Particles must collide with sufficient energy and proper orientation to react.
Reversible Reactions
- Reversible reactions can proceed in both forward and reverse directions.
- Equilibrium is reached when the rates of the forward and reverse reactions are equal, resulting in constant concentrations of reactants and products (ex: N₂ + 3H₂ ⇌ 2NH₃).
Metal Reactions
- Metals react with acids to produce a salt and hydrogen gas (ex: Zn + 2HCl → ZnCl₂ + H₂).
Types of Bonding in Reactions
- Ionic bonding involves the transfer of electrons between a metal and a non-metal.
- Covalent bonding involves the sharing of electrons between two non-metals.
Redox Example: Iron Rusting
- Iron reacts with oxygen to form iron oxide (rust): Fe + O₂ → Fe₂O₃
- Iron is oxidized, and oxygen is reduced.
Factors Affecting Reaction Rate
- Increased temperature increases reaction rate.
- Increased concentration increases reaction rate.
- Increased surface area increases reaction rate.
- The presence of a catalyst increases reaction rate.
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