Chemistry & Chemical Reactivity Chapter 4
36 Questions
0 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What are the numbers in front of the compounds in a chemical equation called?

  • Stoichiometric coefficients (correct)
  • Chemical symbols
  • Reactants
  • Products

    • Which physical state is indicated by the symbol (s) in a chemical equation?

  • Gas
  • Aqueous
  • Solid (correct)
  • Liquid

    • In the reaction 4 Al(s) + 3 O2(g) → 2 Al2O3(s), how many moles of aluminum are needed to react with 3 moles of oxygen?

  • 2 moles
  • 6 moles
  • 1 mole
  • 4 moles (correct)

    • What does the physical state (g) represent in a chemical equation?

    <p>Gaseous state</p> Signup and view all the answers

    Which of the following represents a product formed when zinc reacts with iodine?

    <p>ZnI2</p> Signup and view all the answers

    What is the initial amount of NH4NO3 in moles in the given reaction?

    <p>5.68 mol</p> Signup and view all the answers

    What is the final amount of N2O produced in grams?

    <p>250 g</p> Signup and view all the answers

    If 454 g of NH4NO3 reacts completely, how many moles of H2O are produced?

    <p>11.4 mol</p> Signup and view all the answers

    What is the percent yield of N2O if the actual yield is 131 g?

    <p>52.4%</p> Signup and view all the answers

    Which compound does not appear in the final amounts of the reaction?

    <p>NH4NO3</p> Signup and view all the answers

    What is the total mass of carbon in 0.379 g of CO2?

    <p>0.190 g</p> Signup and view all the answers

    How many moles of hydrogen are present in 0.1035 g of H2O?

    <p>0.250 mol</p> Signup and view all the answers

    Which ratio is used to determine the empirical formula CxHy from the combustion products?

    <p>mol H/mol C</p> Signup and view all the answers

    What assumption is made regarding the carbon and hydrogen in the combustion reaction?

    <p>All carbon in CO2 comes from CxHy.</p> Signup and view all the answers

    If the empirical formula CxHy provides values of x and y, what can be concluded if y is double the value of x?

    <p>The compound has a saturated structure.</p> Signup and view all the answers

    What is the formula to calculate percent yield?

    <p>Percent yield = (actual yield / theoretical yield) x 100%</p> Signup and view all the answers

    In a chemical reaction, what is meant by the limiting reactant?

    <p>The reactant that has the smallest amount limiting the production of products.</p> Signup and view all the answers

    If 5.00 g of H2O is used, what is the expected outcome in terms of product formation?

    <p>Both O2 and H2O can be formed in certain amounts.</p> Signup and view all the answers

    What happens when there is not enough of one reactant in a chemical reaction?

    <p>The reaction ceases once the limiting reactant is used up.</p> Signup and view all the answers

    If theoretical yield exceeds actual yield, what does this indicate?

    <p>Some reactants may have been lost or were insufficient.</p> Signup and view all the answers

    What is the first step in solving a limiting reactant problem?

    <p>Find the limiting reactant</p> Signup and view all the answers

    In a limiting reactant problem, what must be used as the basis for stoichiometry calculations?

    <p>The limiting reactant</p> Signup and view all the answers

    What is typically required to determine the limiting reactant?

    <p>Stoichiometric coefficients from the balanced equation</p> Signup and view all the answers

    Why is finding the limiting reactant critical in a chemical reaction?

    <p>It determines the amount of product formed</p> Signup and view all the answers

    What will happen if you have an excess reactant during the reaction?

    <p>It will remain unreacted</p> Signup and view all the answers

    How does the stoichiometric factor relate to the limiting reactant?

    <p>It provides the ratio of reactants to products</p> Signup and view all the answers

    Which of the following best describes a stoichiometry calculation?

    <p>Converting moles of reactants into mass of products</p> Signup and view all the answers

    What does identifying the limiting reactant allow chemists to predict?

    <p>The maximum yield of product</p> Signup and view all the answers

    In the reaction 2 NO(g) + O2(g) → 2 NO2(g), which reactant is the limiting reactant if NO is present in excess?

    <p>O2</p> Signup and view all the answers

    Which reaction scenario demonstrates a limiting reactant?

    <p>The balloon inflates partially with some reactant left.</p> Signup and view all the answers

    In the equation Zn + 2 HCl → ZnCl2 + H2, how many moles of Zn are required to react with 0.100 mol of HCl?

    <p>0.050 mol</p> Signup and view all the answers

    If 7.00 g of Zn react completely with 0.100 mol of HCl, what can be concluded about the limiting reactant?

    <p>HCl is the limiting reactant.</p> Signup and view all the answers

    What is a characteristic feature of a reaction where one reactant is considered in excess?

    <p>There’s a lower ratio of one reactant compared to the other.</p> Signup and view all the answers

    During the reaction 2 Al + 3 Cl2 → Al2Cl6, if 5.40 g of Al is mixed with 8.10 g of Cl2, which factor would determine the limiting reactant?

    <p>The stoichiometric ratios of Al and Cl2.</p> Signup and view all the answers

    In a reaction represented as A + 2B → C, if you start with 2 moles of A and 1 mole of B, what is the limiting reactant?

    <p>B</p> Signup and view all the answers

    When conducting an experiment, what is the main consequence of having a limiting reactant?

    <p>The amount of product formed is capped by the limiting reactant.</p> Signup and view all the answers

    Study Notes

    Chemistry and Chemical Reactivity

    • The book is titled "Chemistry & Chemical Reactivity"
    • The 6th edition is used
    • The authors are John C. Kotz, Paul M. Treichel, and Gabriela C. Weaver

    Chapter 4: Chemical Equations and Stoichiometry

    • The chapter focuses on chemical equations and stoichiometry
    • Lectures were written by John Kotz
    • Chemical equations depict reactants and products, and their relative amounts in a reaction.
    • Stoichiometric coefficients are the numbers in front of the formulas
    • The letters (s), (g), and (l) denote the physical states of the compounds (solid, gas, liquid)

    Chemical Reactions

    • Reactants are the initial substances
    • Products are the resulting substances
    • Example: Zn + I₂ → ZnI₂ (zinc reacts with iodine to form zinc iodide)
    • This example shows chemical reaction of Zinc (Zn) and Iodine (I₂) to form Zinc Iodide (ZnI₂)

    Chemical Equations

    • Depict the reactants and products and their relative amounts in a reaction
    • Example: 4 Al(s) + 3 O₂ (g) → 2 Al₂O₃ (s)
    • This example illustrates reactants aluminum (Al) and oxygen (O₂) to form product aluminum oxide (Al₂O₃)

    Reaction of Phosphorus with Cl₂

    • Reactants: P₄(s) + 6 Cl₂ (g)
    • Products: 4 PCl₃ (l)
    • Shows stoichiometric coefficients and physical states

    Reaction of Iron with Cl₂

    • Reactants: 2 Fe(s) + 3 Cl₂(g)
    • Products: 2 FeCl₃(s)
    • Shows stoichiometric coefficients and physical states

    Chemical Equations

    • An equation represents a chemical reaction
    • 4 Al (s) + 3 O₂(g) → 2 Al₂O₃ (s)
    • In this reaction, 4 aluminum atoms and 3 oxygen molecules yield 2 aluminum oxide molecules
    • "moles" are units of measurement representing number of molecules

    Chemical Equations

    • The total number of atoms of each element remains the same before and after a reaction
    • Explained via Law of Conservation of Matter

    Chemical Equations

    • Chemical equations need to be balanced
    • This means the same number of atoms of each element must be present on both sides of the equation
    • An example was shown from Lavoisier 1788

    Balancing Equations

    • Example: —Al(s) + —Br₂(liq) → —Al₂Br₆(s)
    • A balanced equation shows the correct coefficients for the compounds

    Balancing Equations

    • More examples of balanced equations are given such as C₃H₈ + O₂ → CO₂ + H₂O and B₄H₁₀ + O₂ → B₂O₃ + H₂O

    Stoichiometry

    • The study of the quantitative aspects of chemical reactions.

    Stoichiometry

    • It is based on the principle of conservation of matter
    • Example: 2 Al(s) + 3 Br₂(liq) → 2 AlBr₃(s)

    Problem (NH₄NO₃)

    • 454 g of NH₄NO₃ decomposes into N₂O and 2 H₂O
    • The calculation shows theoretical yield amounts
    • Amount table is used to analyze different reactions
    • This example involves conservation of matter

    General Plan for Stoichiometry Calculations

    • A general approach for stoichiometry calculations is explained
    • The process involves converting mass of reactants to moles of reactants
    • A stoichiometric factor is used to relate moles of reactants to moles of products
    • Finally, moles of products are converted back into mass of products

    Problem (H₂O₂)

    • A problem to compute the mass of O₂ and H₂O given the mass of H₂O₂

    Reactions Involving a Limiting Reactant

    • In some reactions, there is not enough of one reagent to completely use the other reactant
    • This particular reagent limits the product formation
    • The limiting reactant determines the amount of product that can be formed.
    • Example 1: Zn + 2HCl → ZnCl₂ + H₂
    • Example 2: 2 NO + O₂ → 2 NO₂

    Limiting Reactants

    • Shows a real example to help determine if one or two possible reactants is the limiting reactant

    Limiting Reactants

    • Demonstrates how to calculate mass of different reactants to determine limiting reactant via example
    • A ratio of limiting reactant and other reactant is calculated

    Reaction to be studied

    • Example: 2 Al + 3 Cl₂ → Al₂Cl₆
    • This chemical reaction is discussed
    • Demonstrates different chemical reactions

    Problem (Al + Cl₂)

    • A problem to calculate the mass of Al₂Cl₆ that can form when mixing 5.40 g of Al with 8.10 g of Cl₂
    • Shows how to calculate the mass of product (Al₂Cl₆) given the amounts and stoichiometry of the reactants

    Limiting Reactants

    • Step 1: Calculate the limiting reactant to decide which reactant limits the amount of product that can be produced
    • Step 2: Use the limiting reactant as the basis for the stoichiometry calculation

    Limiting Reactants

    • Shows how to calculate how much of which reactants will be left over after the reaction is complete. For example, use of Al and Cl₂

    Chemical Analysis

    • Details chemical analysis involving various reactions between compounds
    • An example is given in a chemical reaction
    • The solution of Na₂SO₄ (aq) and BaCl₂ (aq) to form solid BaSO₄
    • The mass percent of Na₂SO₄ in the impure sample of thenardite is determined

    Determining the Formula of a Hydrocarbon by Combustion

    • Describes an experiment where a hydrocarbon is burned to determine its empirical formula, using the combustion products to calculate the moles of carbon and hydrogen

    Using Stoichiometry to Determine a Formula

    • Burn 0.115 g of a hydrocarbon (CₐHₓ)
    • Determine the empirical formula given the mass of CO₂ and H₂O produced in the combustion reaction

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Related Documents

    Chemistry and Chemical Reactivity 6th Edition PDF

    Description

    Explore the fundamentals of chemical equations and stoichiometry in Chapter 4 of 'Chemistry & Chemical Reactivity'. Understand the role of reactants, products, and stoichiometric coefficients in representing chemical reactions. This quiz will challenge your knowledge with examples and concepts crucial for mastering chemical reactions.

    More Like This

    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser