Chemistry Chapter 5 Flashcards

Questions and Answers

Reactants and products in a chemical equation are arranged how?

Reactants on the left, products on the right (correct)

Reactants and products are mixed

Reactants on the right, products on the left

There is no specific arrangement

What type of reaction does calcium carbonate undergo when heated strongly?

Decomposition

What is a limiting reactant?

The substance that is depleted first and stops a reaction

What are the coefficients that properly balance the equation NaOH + H2S --> Na2S + H2O?

2, 1, 1, 2 Signup and view all the answers

What type of reaction is represented by CaCO3 --> CaO + CO2?

Decomposition Signup and view all the answers

What is the mole ratio to convert from KO2 to oxygen in the equation KO2 + H2O --> KOH + O2?

3 mol O2 / 4 mol KO2 Signup and view all the answers

How many moles of S8 can be produced from 0.250 mole of SO2 in the reaction 16H2S + 8SO2 --> 16H2O + 3S8?

0.0938 mole Signup and view all the answers

What is the percent yield for the combustion of ethanol given 75.0 g C2H5OH reacted with 105 g O2 and produced 65.0 g CO2?

67.5% Signup and view all the answers

If 10.0 moles of potassium react, how many moles of bromine are required according to 2K + Br2 --> 2KBr?

5.00 Signup and view all the answers

Which reactant is the limiting reactant when 2.00 grams of potassium react with 2.00 grams of bromine in 2K + Br2 --> 2KBr?

Br2 Signup and view all the answers

What mass of potassium chloride can be produced from 5.2 g of potassium and 7.9 g of chlorine in 2K + Cl2 --> 2KCl?

9.9 g KCl Signup and view all the answers

[Blank] lower the [Blank] of a reaction and therefore increase the reaction rate.

Catalysts, activation energy Signup and view all the answers

What is a synthesis reaction?

2 or more elements or compounds combine to form one or more complex compounds A + B --> AB Signup and view all the answers

What occurs in a decomposition reaction?

Breakdown of one compound to form elements or simpler compounds AB --> A + B Signup and view all the answers

What characterizes a single replacement reaction?

One element trades places with a different element A + BC --> AC + B Signup and view all the answers

What characterizes a double replacement reaction?

One element trades places with a different element in a compound AB + CD --> AD + CB Signup and view all the answers

What is reduction in a chemical reaction?

Gain of one or more electrons Signup and view all the answers

What is oxidation?

Loss of one or more electrons Signup and view all the answers

What are redox reactions?

Involves transfer of electrons, oxidation and reduction ALWAYS occur together Signup and view all the answers

What is the oxidizing agent?

The thing that is reduced is the oxidizing agent Signup and view all the answers

What are reducing agents?

The thing that is oxidized is the reducing agent Signup and view all the answers

What is stoichiometry?

Study of moles and mass relationships in a chemical reaction; coefficients refer to the number of moles of the compound Signup and view all the answers

How many moles of Cl2 are required to produce 9.6 moles of PCl3 in the reaction P4 + 6Cl2 --> 4PCl3?

14.4 moles Signup and view all the answers

If excess H2O is present, what masses of NH3 and CO2 are produced from 0.92 moles of urea?

31.4 grams Signup and view all the answers

How many grams of NaCl will be produced by 6.5 grams of NaHCO3 in the reaction NaHCO3 + HCl --> NaCl + H2O + CO2?

4.5 g NaCl Signup and view all the answers

What is a limiting reagent?

The reagent used up first in a chemical reaction Signup and view all the answers

What are excess reagents?

Total reactant - reactant used = excess reactant Signup and view all the answers

What is theoretical yield?

The maximum amount of product that can be obtained Signup and view all the answers

Percent yield is the same as actual yield.

False Signup and view all the answers

What is actual yield?

Amount of product obtained from a reaction Signup and view all the answers

What is free energy in a reaction?

Energy released or gained in a reaction; sum of energy of bonds broken and bonds made Signup and view all the answers

What are spontaneous reactions?

Negative value, energy is released, continue by themselves once it has started Signup and view all the answers

What are nonspontaneous reactions?

Will not take place unless something starts them and keeps them going; positive value, energy consumed Signup and view all the answers

What defines an exothermic reaction?

Combustion reaction releases energy in the form of heat Signup and view all the answers

What defines an endothermic reaction?

Energy is added to the system for the reaction to occur Signup and view all the answers

What happens to reaction rate if you lower the activation energy?

Reaction rate is increased Signup and view all the answers

What happens when you add a catalyst to a reaction?

Lowers the activation energy Signup and view all the answers

Study Notes

Chemical Reactions

Reactants and Products: Reactants are positioned on the left, products on the right of a chemical equation.
Decomposition Reaction: Calcium carbonate (CaCO3) decomposes when heated to form calcium oxide (CaO) and carbon dioxide (CO2).
Limiting Reactant: The limiting reactant is the substance that is consumed first, halting the reaction.

Balancing Chemical Equations

Balanced Equation Coefficients: For the equation NaOH + H2S → Na2S + H2O, the coefficients are 2, 1, 1, and 2, respectively.
Mole Ratios: When balancing KO2 + H2O → KOH + O2, the mole ratio of O2 to KO2 is 3 mol O2/4 mol KO2.

Mole Calculations

Sulfur Production: From the reaction 16H2S + 8SO2 → 16H2O + 3S8, 0.250 mole of SO2 produces 0.0938 mole of S8.
Percent Yield of Ethanol Combustion: The combustion of 75.0 g of ethanol gives a percent yield of 67.5% for the production of CO2.
Moles of Reactants: In the reaction 2K + Br2 → 2KBr, 10.0 moles of potassium require 5.00 moles of bromine.
Limiting Reactant in a Potassium and Bromine Reaction: In the reaction of 2.00 grams each of potassium and bromine, bromine (Br2) is the limiting reactant.
Mass Calculation of Potassium Chloride: From 5.2 g of potassium and 7.9 g of chlorine, 9.9 g of potassium chloride (KCl) can be produced.

Reaction Types

Catalysts: Catalysts lower the activation energy, enhancing the reaction rate.
Synthesis Reaction: Involves combining multiple elements or compounds to form one complex product (A + B → AB).
Decomposition Reaction: A single compound breaks down into simpler substances (AB → A + B).
Single Replacement Reaction: One element replaces another in a compound (A + BC → AC + B).
Double Replacement Reaction: Elements in two compounds exchange partners (AB + CD → AD + CB).

Redox Reactions

Reduction: The gain of electrons during a reaction.
Oxidation: The loss of electrons during a reaction.
Redox Reactions: These always involve both oxidation and reduction processes and electron transfer.

Stoichiometry

Stoichiometry: The study of relationships between moles and mass in chemical reactions; coefficients signify the number of moles.
Limiting and Excess Reagents: The limiting reagent is consumed first, while excess reagents are leftover reactants after the reaction.
Theoretical Yield: The highest possible quantity of product produced from a given amount of reactants.

Yield and Free Energy

Actual Yield: The real amount of product obtained from a chemical reaction.
Free Energy: Energy gained or released in a reaction based on bond breaking and formation.
Spontaneous Reactions: Occur without ongoing input of energy and have a negative free energy value.
Nonspontaneous Reactions: Require energy input to proceed and have a positive free energy value.

Reaction Dynamics

Exothermic Reactions: Release heat energy, common in combustion processes.
Endothermic Reactions: Absorb energy to proceed, requiring external energy input.
Reaction Rate: The speed at which products form in a reaction.
Activation Energy (Eact): The barrier energy necessary to transition from reactants to products; reducing the activation energy increases the reaction rate.
Factors Affecting Reaction Rate: Changing temperature, concentration, or adding a catalyst can alter the speed of a reaction.

Key Outcomes

Lowering Activation Energy: Increases reaction rate, facilitating faster product formation.
Adding Catalysts: Permanently lowers activation energy and accelerates reactions without being consumed.

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Description

Test your knowledge of key concepts from Chemistry Chapter 5 with these flashcards. Each card provides definitions and examples related to chemical equations, reactants, products, and reaction types. Perfect for mastering the foundational elements of chemical reactions.