Chemistry: Oxidation and Reduction Concepts
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Questions and Answers

What does the acronym OILRIG stand for in relation to oxidation and reduction?

  • Oxidation Is Loss, Reduction Is Growth
  • Oxidation Increases Loss, Reduction Increases Gain
  • Oxidation Is Loss, Reduction Is Gain (correct)
  • Oxidation Increases Loss, Reduction Increases Growth

    • Zinc is getting reduced in the half reaction Zn (s) → Zn2+ (aq) + 2e-.

    False

    What is produced from the complete combustion of hydrocarbons?

    Carbon dioxide and water

    At Standard Temperature and Pressure (STP), 1 mole of gas occupies _____ L of space.

    <p>22.7</p> Signup and view all the answers

    Match the following elements with their respective reactions:

    <p>Zinc = Oxidation Copper = Reduction Magnesium = Oxidation Aluminum = Reduction</p> Signup and view all the answers

    Which of the following is a true statement about half-reactions?

    <p>They are useful to see what happens in an overall redox reaction.</p> Signup and view all the answers

    Complete combustion produces carbon monoxide as a primary product.

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

    In a reaction involving silver ions and aluminum metal, which species is oxidized?

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

    How many times must reaction 1 be performed based on the provided coefficients?

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

    The combustion of metals produces metal hydroxides.

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

    What is the product formed when hydrogen combusts with oxygen?

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

    Sulfur combustion can lead to the formation of _______.

    <p>acid rain</p> Signup and view all the answers

    Match the following reactions with their products:

    <p>2H2 + O2 = Water S + O2 = SO2 2Sr + O2 = 2SrO 4K + O2 = 2K2O</p> Signup and view all the answers

    What is the primary effect of combustion products in water?

    <p>Increase in acidity</p> Signup and view all the answers

    The co-efficient of hydrogen in the target indicates that reaction 2 needs to be performed one full time.

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

    What process is primarily concerned with hydrocarbons and alcohols in terms of energy production?

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

    What is the specific heat capacity of pure water?

    <p>4.18 kJ kg-1 K-1</p> Signup and view all the answers

    The process of bond breaking is exothermic.

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

    What is the enthalpy change of combustion denoted as?

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

    The enthalpy change of formation occurs when one mole of a substance is formed from its elements in their __________ states.

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

    Match the following terms with their definitions:

    <p>Exothermic = Heat given out to surroundings Endothermic = Heat input required from surroundings ΔHfᶱ = Enthalpy change of formation ΔHcᶱ = Enthalpy change of combustion</p> Signup and view all the answers

    What is the enthalpy change when two hydrogen atoms combine to form a hydrogen molecule?

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

    Standard conditions are defined as a temperature of 298 K and a pressure of 100 kPa.

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

    What does average bond enthalpy refer to?

    <p>The average energy to break one mole of a bond in similar compounds in the gaseous state.</p> Signup and view all the answers

    What is the standard enthalpy change denoted by ΔHo?

    <p>The enthalpy change for standard conditions</p> Signup and view all the answers

    Calorimetry measures absolute enthalpies for reactions.

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

    The enthalpy of combustion for DME was found to be ______ kJ/mol.

    <p>-1406.4</p> Signup and view all the answers

    Match the following concepts with their definitions:

    <p>Enthalpy of Combustion = Energy change when a substance is burned in oxygen Specific Heat Capacity = Energy required to raise the temperature of a substance Calorimetry = Measurement of heat changes in physical and chemical processes Standard States = Forms of substances at standard temperature and pressure</p> Signup and view all the answers

    If you have 100 kg of water, how much energy is needed to raise its temperature by 1 K?

    <p>418 kJ</p> Signup and view all the answers

    Why might there be a discrepancy between the calculated enthalpy and the literature value?

    <p>Products and reactants may not be in standard states.</p> Signup and view all the answers

    In calorimetry, the formula used is ______, where m is the mass, c is the specific heat, and ΔT is the temperature change.

    <p>q = mcΔT</p> Signup and view all the answers

    What is the main product of complete combustion?

    <p>Carbon dioxide</p> Signup and view all the answers

    Incomplete combustion produces more energy than complete combustion.

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

    What is the specific energy of octane in kJ/kg?

    <p>47860</p> Signup and view all the answers

    The incomplete combustion of hydrocarbons can produce ______ as a pollutant.

    <p>carbon monoxide</p> Signup and view all the answers

    Match the following types of fuels with their characteristics:

    <p>Natural gas = Mostly methane Crude oil = Complicated mixture of hydrocarbons Coal = Different carbon content Butane = Common alkane fuel</p> Signup and view all the answers

    Which of the following statements about specific energy is true?

    <p>Specific energy is the energy released per kilogram of fuel combusted.</p> Signup and view all the answers

    Energy density refers to energy released per mole combusted.

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

    What type of combustion produces both carbon monoxide and water?

    <p>incomplete combustion</p> Signup and view all the answers

    In the reaction P4 + 6Cl2 → 4PCl3, which reagent is limiting if you have 147 g of P4 and 615 g of Cl2?

    <p>P4</p> Signup and view all the answers

    The theoretical yield is the actual amount of product obtained from a chemical reaction.

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

    What is the definition of atom economy?

    <p>Atom economy is a measure of how efficiently a process converts starting materials into useful products.</p> Signup and view all the answers

    A solution with a molarity of 1.0 M contains ______ mole of solute dissolved in 1 L of solution.

    <p>1</p> Signup and view all the answers

    Which reaction is an example of a net ionic equation?

    <p>Ag+ (aq) + Cl- (aq) → AgCl (s)</p> Signup and view all the answers

    An ionic equation can sometimes be simplified to a net ionic equation.

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

    What could increase the atom economy in a chemical reaction?

    <p>Finding a use for byproducts produced in the reaction.</p> Signup and view all the answers

    Study Notes

    Warm-Up 11/11 - 11/12

    • Sucrose is a covalent molecule
    • Sucrose is likely soluble in water due to its polar structure.
    • Sucrose likely has a large number of hydroxyl groups (-OH) creating dipole-dipole interactions with water.

    Mols, Stoich and Thermo

    • Units Covered: S1.4, R2.1, R1.1-1.3
    • Topics to review: moles, molecular/empirical formulae, stoichiometry, and thermochemistry

    From now 'till 2025

    • Review moles, molecular/empirical formulae
    • Review stoichiometry
    • Review thermochemistry (R1.1-R1.3)

    S1.4 - Counting Particles - The Mole

    • The mole (mol) is the SI unit of amount of substance
    • One mole of an entity contains 6.02 x 10²³ of that entity

    Mols - Example problem

    • If you have 2 mols of water molecules:
      • You will have 2 mols of oxygen atoms.
      • You will have 4 mols of hydrogen atoms.

    Why moles?

    • Chemical reactions occur proportionally
    • Coefficients in a chemical reaction represent the ratio of moles of reactants and products

    An aside - atomic masses

    • Relative atomic mass (Ar) is the weighted mean of the naturally occurring isotopes
    • Relative atomic mass has no units; it is a ratio
    • Actual atomic mass is measured in grams per mole

    Molar masses

    • Molar mass is the mass of one mole of a substance
    • Molar mass is given the symbol M and has units of g/mol
    • Example: Molar mass of helium is 4.00 g/mol

    Example problem

    • If you have one mole of water:
      • You will have 16.00 g of oxygen
      • You will have 2.02 g of hydrogen

    Molar masses

    • For covalent molecules, use molecular mass
    • For ionic compounds, use formula mass
    • This information is found in the data booklet

    Recall dimensional analysis

    • Dimensional analysis is a technique for converting units
    • To use it, first identify your givens and your goal
    • Then identify the conversion factors that will help you convert to your goal

    Dimensional analysis time

    • Convert 10 grams of water to moles using molar mass

    Practice - deduce the amount/mass of different substances

    • Deduce the amount of ammonia (in moles) for a given mass of ammonia and/or a given number of ammonia molecules
    • Deduce the mass of calcium carbonate for a given number of moles
    • Deduce mass of hydrogen for a given number of atoms

    Empirical formula

    • The empirical formula represents the simplest whole number ratio of atoms in a molecule
    • It can be calculated from masses of the elements or percentage composition by mass.

    Empirical formula tips

    • The empirical formula shows the simplest whole number ratio of atoms in a substance
    • The percentage of each element can be used to calculate the empirical formula
    • You can assume 100 grams of substance to simplify the calculation

    Emp. example prob

    • A hydrocarbon contains 85.7% by mass of carbon. Calculate the empirical formula

    Molecular formula

    • The molecular formula shows the actual number of atoms of each element in a compound
    • It can be determined from the empirical formula and the molar mass of the molecule

    More molecular formula practice

    • Determine the molecular formula of a compound, given the empirical formula and the relative molecular mass

    "Mol airlines"

    • Identify chemicals quickly
    • Write a one sentence 'report' for each chemical
    • Complete this on the back of the paper.

    Mols

    • There are more atoms in a small amount of sugar than there are stars in the universe

    Mol of sugar vs EVERY STAR IN THE SKY

    • Sugar has a much higher number of atoms per structure than the number of stars in the universe
    • The molecular formula for sugar is C₁,₂H₂₂O₁₁

    "All the stars in the sky are our enemy"

    • A mole of sugar contains 135 times more atoms than the number of stars in the universe

    R2.1 - Stoichiometry

    • Stoichiometry is the study of the numerical relationships between reactants and products in a balanced chemical reaction.
    • Stoichiometric calculations involve moles.
    • Mass to mass problems, moles to moles problems, and moles to mass are possible

    Stoich Problems - Mol to Mol / Mass to Mol

    • If you have a certain number of moles of one substance, the ratio of moles of reactants and products can be used to determine the moles of another substance

    Stoich Problems - Mol to Mass / Mass to Mass

    • If you have a certain number of grams of one substance, you can use the molar mass and mole ratios of reactants and products to determine the moles/mass of another substance

    Limiting Reagents - Burger...

    • Limiting reagents describe a situation when one reactant is used up first in a reaction.
    • Determine the maximum number of cheeseburgers that can be made with a given amount of patties, buns, and cheese

    Limiting Reagent / Limiting Reactant

    • The limiting reagent is determined by finding the theoretical yield of the reactant that produces the smallest number of moles of products
    • Determine which reactant will be used up first
    • The limiting reagent limits the amount of product that can be formed

    Worked example

    • Calculate the amount (in moles) of sodium chloride produced when a specific amount of sodium reacts with chlorine

    Limiting Reagent Problems

    • P₄ + 6Cl₂ → 4PCl₃. Determine the amount of PCl₃

    Warm-Up on whiteboard

    • This refers to a given warm-up activity for the class

    Theoretical vs Experimental Yield

    • Theoretical yield is the maximum amount of product possible
    • Experimental yield is the amount of product obtained in a reaction

    Example

    • Given an experimental yield and a theoretical yield, determine the percentage yield

    Bromine reacts with ethene to form 1,2-dibromoethane

    • In a given reaction, calculate the percentage yield of a compound

    Atom Economy

    • Atom economy is a measure of how many atoms of the desired product are produced in a chemical reaction
    • Atom economy takes into account the waste produced in reactions
    • Calculate the atom economy for a specific reaction

    Task 1

    • Identify the compounds produced in a given reaction of chlorine gas and ethene
    • Use data to calculate the atom economy
    • Determine maximum theoretical yield of the product given the mass of reactants
    • Determine the percentage yield of the product given the experimental yield

    Concentration

    • A molar solution (M or mol/L) is a solution of one mole of solute dissolved in one liter of solution
    • Concentration is measured in moles per liter or moles per cubic decimeter

    Practice - Calculate the mass/concentration of substances in a solution

    • Calculate mass of sodium hydroxide present in a given solution
    • Calculate the concentration of the solution from the mass of a chemical compound

    Ionic Equations

    • In a double replacement reaction where a precipitate (solid) forms, the net ionic equation is the overall equation that only includes the ions that participate in the reaction.
    • Spectator ions are the ions that do not participate in the reaction.

    Half Reactions

    • Oxidation is the loss of electrons
    • Reduction is the gain of electrons

    Standard Temperature and Pressure (STP)

    • STP is defined as a temperature of 273.15 K and a pressure of 100 kPa
    • Used for gas calculations and gas stoichiometry

    Post Thanksgiving Break Warm-Up

    • Given a balanced chemical equation, initial mass of substance, and a given number of moles of a second substance, calculate the mass of the product

    Reminder of the ideal gas law

    • Ideal gas law describes the gas law PV=nRT, which relates pressure, volume, number of moles, and absolute temperature of a gas
    • The ideal gas constant (R) is useful for stoichiometry reactions involving gases

    Complete Combustion

    • Complete combustion involves a hydrocarbon reacting with oxygen to form carbon dioxide and water.
    • Complete combustion is used in many industrial processes

    Ex: Complete Combustion

    • Write a balanced chemical equation for complete combustion of different compounds

    Multiple Choice Work Time

    • Skip some practice questions for multiple choice

    R1.3 - Intro

    • This unit deals with thermodynamics
    • Chemical reactions involve energy changes

    Combustion of metals

    • When a metal reacts with oxygen, metal oxides are produced, which can be basic

    Combustion of non-metals

    • Some nonmetal combustion reactions produce acid rain
    • Combustion reactions create various oxides

    Complete Combustion of Hydrocarbons/Alcohols

    • Complete combustion reactions produce carbon dioxide and water
    • Fuels (alkanes and alcohols) are hydrocarbons

    Practice - Write equations for complete combustions

    • Write equations describing complete combustion reactions for given chemical compounds

    Incomplete combustion of hydrocarbons

    • Incomplete combustion reactions form carbon monoxide (often a pollutant) or solid carbon

    • Incomplete combustion reactions are less exothermic than complete combustion

      Practice - Write equations for incomplete combustions

    • Write equations for incomplete combustions for given chemical compounds

    Why is oil still the dominant fuel?

    • Oil has higher specific energy than other sources

    • Logistical factors make it easier to use oil than other energy sources.

      Specific Energy

    • Calculate specific energy using dimensional analysis and the molar mass of the compound

    Specific Energy Implication

    • Octane has a greater specific energy than ethanol
    • This means releasing energy from equal masses of octane and ethanol, octane releases more energy

    Energy density

    • Enthalpy of combustion measures energy released per mole of a substance during combustion
    • Specific energy measures energy released per unit mass during combustion
    • Energy density measures energy released per unit volume during combustion

    Fossil Fuels

    • Fossil fuels are coal, crude oil, and natural gas
    • Natural gas is mostly methane
    • Crude oil is a mixture of hydrocarbons
    • Different coal types have varying carbon percentages and specific energy values

    Fossil fuel - Advantages / Disadvantages

    • Fossil Fuels are compared in terms of advantages and disadvantages

    Intro to Fuel Cells

    • Fuel cells convert chemical energy to electrical energy

    1/15 - 1/16 Warm-Ups

    • Write the incomplete combustion equation for propane
    • Using section 12 in the data booklet, calculate the enthalpy of a reaction for the given reactants and products, and calculate percentage error

    Brief, Post-Break, R1.1 Review

    • Temperature measures the average kinetic energy of molecules
    • Heat is a form of energy

    Standard Enthalpy Changes

    • The enthalpy change is measured at standard conditions (298 K and 100 kPa)
    • By convention, standard enthalpy changes are given the symbol ΔH°

    Calorimetry

    • Calorimetry is a technique that measures changes in heat flow during chemical and physical processes
    • Specific heat capacity of water is 4.18 kJ/kg•K

    Specific Heat Practice

    • Calculate the amount of energy needed to heat up a quantity of water
    • Calculate the final temperature of iron when the same amount of energy is added

    Calorimetry - "Coffee Cup" Style

    • Coffee cup calorimetry measures the heat released or absorbed in a chemical reaction in solution

    Calorimetry - "Bomb" Style

    • Bomb calorimetry measures energy changes in combustion

    The standard enthalpy change of combustion

    • Determine the mass of a given chemical that would increase a given mass of water's temperature by a specific amount

    1.1 MC Practice

    • Solve multiple-choice questions about chemical reactions and enthalpy changes

    1/17 - 1/22 Warm Up

    • Calculate the temperature change when a given volume of propane is ignited in a bomb calorimeter, and a given amount of water is present.

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    Mols, Stoich, and Thermo! PDF

    Description

    Test your knowledge of oxidation and reduction principles, including the acronym OILRIG and various half-reactions. This quiz covers concepts related to combustion, reactions of hydrocarbons, and the products formed in chemical reactions. Ideal for chemistry students looking to enhance their understanding.

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