Questions and Answers
What is a chemical equation?
What are reactants?
Substances that undergo change in a chemical reaction.
What are products?
New substances formed as a result of a chemical reaction.
The law of conservation of mass states that mass is created in a chemical reaction.
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Why must chemical reactions be balanced?
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How do you balance chemical equations?
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What is a synthesis reaction?
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What is a decomposition reaction?
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What is a single-replacement reaction?
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What is a double-replacement reaction?
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What is a combustion reaction?
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What is a REDOX reaction?
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What did the discovery of particles allow scientists to do?
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What do chemical reactions involve?
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What happens to energy during a chemical reaction?
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What is an exothermic reaction?
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What is an endothermic reaction?
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What is the law of conservation of energy?
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Which factors affect a chemical reaction?
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How does temperature affect chemical reactions?
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How does surface area affect chemical reactions?
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How does stirring affect chemical reactions?
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How does concentration affect chemical reactions?
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What are catalysts?
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What is the difference between oxidation and reduction?
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Which of the following does NOT state the arrow's meaning in a chemical reaction?
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Why does '1 atom reacting with 1 atom of O to produce a unit of MgO that contains 2 atoms' not show the law of conservation of mass?
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Which of the following accurately represents what happens when sulfur and oxygen react to form sulfur trioxide?
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What two types of reactions take place when magnesium carbonate reacts with nitric acid?
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What are the products of the double replacement reaction between potassium chloride and silver acetate?
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Explain why chemical reactions must be balanced.
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Study Notes
Chemical Equations and Reactions
- A chemical equation represents a chemical reaction with reactants and products depicted as formulas.
- Reactants are substances that undergo change in a chemical reaction.
- Products are new substances formed as a result of a chemical reaction.
- According to the Law of Conservation of Mass, mass is neither created nor destroyed in a chemical reaction, necessitating balanced equations.
- Chemical equations are balanced to demonstrate that mass is conserved during a reaction.
Balancing Chemical Equations
- Balancing chemical equations involves changing the coefficients, or the numbers before the formulas.
- Different types of reactions include:
- Synthesis Reaction: Two or more substances react to form a single substance (A + B → AB).
- Decomposition Reaction: A compound breaks down into two or more simpler substances (AB → A + B).
- Single-replacement Reaction: One element replaces another in a compound (A + BC → B + AC).
- Double-replacement Reaction: Two compounds exchange ions to form two new compounds (AB + CD → AD + CB).
- Combustion: A substance reacts rapidly with oxygen, producing heat and light (e.g., CH₄ + 2O₂ → CO₂ + 2H₂O).
- REDOX Reaction: Involves the transfer of electrons, where they are both gained and lost.
Energy and Reactions
- During a chemical reaction, energy may be either released or absorbed.
- An exothermic reaction releases energy to its surroundings, while an endothermic reaction absorbs energy from the surroundings.
- The Law of Conservation of Energy states that energy cannot be created or destroyed but can be transferred or transformed.
Factors Affecting Chemical Reactions
- Factors that influence chemical reactions include:
- Temperature: Increasing temperature enhances particle movement, leading to more collisions and reactions.
- Surface Area: Larger surface area allows for increased exposure of reactants, promoting collisions.
- Stirring: Enhances the rate of interactions between reactants, resulting in more collisions.
- Concentration: Higher concentration of reactants leads to an increased frequency of collisions.
- Catalysts: Substances that accelerate reactions without being consumed, functioning independently of reactants and products.
Understanding Oxidation and Reduction
- Oxidation occurs when metals lose electrons, while reduction happens when nonmetals gain electrons.
Misconceptions and Clarifications
- The term conserves does not denote chemical reaction representation, unlike terms such as forms, produces, or yields, which indicate production.
- A reaction involving one atom of magnesium reacting with one atom of oxygen fails to demonstrate the Law of Conservation of Mass due to oxygen's diatomic nature (O₂).
- The balanced equation 2S + 3O₂ → 2SO₃ accurately represents the reaction of sulfur and oxygen forming sulfur trioxide.
Types of Reactions in Processes
- The reaction between magnesium carbonate (MgCO₃) and nitric acid (HNO₃) results in both double-replacement and decomposition reactions.
- Products from the reaction of potassium chloride and silver acetate include potassium acetate and silver chloride, represented as KCl + AgC₂H₃O₂ → KC₂H₃O₂ + AgCl.
Importance of Balance in Chemical Reactions
- Balancing chemical reactions is essential to confirm that the mass of reactants equals the mass of products, thereby affirming the conservation of mass principle.
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Description
Test your knowledge on chemical equations and reactions, including the identification of reactants and products. Explore the importance of balancing chemical equations and different types of reactions, such as synthesis, decomposition, and single-replacement. This quiz will reinforce your understanding of the Law of Conservation of Mass.
