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Chemical reactions in which reduction and oxidation takes place are known as what?
Chemical reactions in which reduction and oxidation takes place are known as what?
Redox reactions
Which of these is a classical definition of oxidation?
Which of these is a classical definition of oxidation?
The modern concept of oxidation and reduction is based on electron transfer.
The modern concept of oxidation and reduction is based on electron transfer.
True
What is the oxidation number of an element in a species called?
What is the oxidation number of an element in a species called?
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What is the oxidation number of hydrogen in H₂?
What is the oxidation number of hydrogen in H₂?
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What is the oxidation number of oxygen in H₂O?
What is the oxidation number of oxygen in H₂O?
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What is the oxidation number of sulfur in Na2SO4?
What is the oxidation number of sulfur in Na2SO4?
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What is the oxidation number of phosphorus in P4?
What is the oxidation number of phosphorus in P4?
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What is the oxidation number of chlorine in Cl2?
What is the oxidation number of chlorine in Cl2?
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What is the oxidation number of fluorine in its compounds?
What is the oxidation number of fluorine in its compounds?
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What is the general oxidation number of hydrogen in its compounds?
What is the general oxidation number of hydrogen in its compounds?
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What is the general oxidation number of oxygen in oxides?
What is the general oxidation number of oxygen in oxides?
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What is the oxidation number of oxygen in peroxides?
What is the oxidation number of oxygen in peroxides?
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What is the maximum possible oxidation number of an element in a species?
What is the maximum possible oxidation number of an element in a species?
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Which element is the most electronegative element and what is its oxidation number?
Which element is the most electronegative element and what is its oxidation number?
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All IA group elements show +1 oxidation number in their compounds.
All IA group elements show +1 oxidation number in their compounds.
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The sum of oxidation numbers of all atoms in a compound is always equal to zero.
The sum of oxidation numbers of all atoms in a compound is always equal to zero.
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What is the process known as, where the oxidation number of an element increases during a chemical reaction?
What is the process known as, where the oxidation number of an element increases during a chemical reaction?
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Oxidation and reduction can occur independently of each other.
Oxidation and reduction can occur independently of each other.
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What is a substance called that oxidizes another substance by getting reduced itself?
What is a substance called that oxidizes another substance by getting reduced itself?
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What is a substance called that reduces another substance by getting oxidized itself?
What is a substance called that reduces another substance by getting oxidized itself?
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What is a chemical reaction called where an element present in a single oxidation state at the reactant side converts into two different oxidation numbers at the product side, showing both oxidation and reduction?
What is a chemical reaction called where an element present in a single oxidation state at the reactant side converts into two different oxidation numbers at the product side, showing both oxidation and reduction?
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What is the reverse reaction of disproportionation called?
What is the reverse reaction of disproportionation called?
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What are two methods for balancing redox reactions?
What are two methods for balancing redox reactions?
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What is the basic unit of concentration for solutions?
What is the basic unit of concentration for solutions?
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What is the n-factor of a substance called in redox reactions?
What is the n-factor of a substance called in redox reactions?
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The n-factor of a substance can have a negative value.
The n-factor of a substance can have a negative value.
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In a chemical reaction, equivalent of reactants and products are always what?
In a chemical reaction, equivalent of reactants and products are always what?
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What is the process called where a solution of known concentration is added to a solution of unknown concentration until the reaction is complete.
What is the process called where a solution of known concentration is added to a solution of unknown concentration until the reaction is complete.
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What is the point in a titration when the reaction is complete called?
What is the point in a titration when the reaction is complete called?
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What methods are used to determine the strength of a reducing agent?
What methods are used to determine the strength of a reducing agent?
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What is the process called where the excess of a reagent in a reaction is titrated with a standard solution?
What is the process called where the excess of a reagent in a reaction is titrated with a standard solution?
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What is the point in a titration when an indicator is added to the solution, signaling the completion of the reaction?
What is the point in a titration when an indicator is added to the solution, signaling the completion of the reaction?
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What kind of titration involves a process where two different equivalence points are detected by two different indicators?
What kind of titration involves a process where two different equivalence points are detected by two different indicators?
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Water containing high concentrations of Ca²⁺ and Mg²⁺ ions is called soft water.
Water containing high concentrations of Ca²⁺ and Mg²⁺ ions is called soft water.
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What are the two types of water hardness?
What are the two types of water hardness?
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What is the process called that removes hardness from water?
What is the process called that removes hardness from water?
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What method can be used to remove temporary hardness?
What method can be used to remove temporary hardness?
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Which of the following is the correct equation for the reaction of Ca(HCO₃)₂ with Na₂CO₃?
Which of the following is the correct equation for the reaction of Ca(HCO₃)₂ with Na₂CO₃?
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What is the general name for the process of exchanging ions using specific materials to remove hardness?
What is the general name for the process of exchanging ions using specific materials to remove hardness?
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What is the name of the process that uses sodium zeolite to remove hardness?
What is the name of the process that uses sodium zeolite to remove hardness?
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What is the chemical name for the chemical compound Na₂[Na₄(PO₃)₆]?
What is the chemical name for the chemical compound Na₂[Na₄(PO₃)₆]?
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Which of these is NOT a method used to remove hardness from water?
Which of these is NOT a method used to remove hardness from water?
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Study Notes
Redox Reactions
- Chemical reactions involving both reduction and oxidation are known as redox reactions.
- Oxidation traditionally refers to the gain of oxygen or the loss of hydrogen.
- The modern definition of oxidation and reduction focuses on electron transfer.
- The oxidation number of an element in a species represents its apparent charge.
- The oxidation number of hydrogen in H₂ is 0.
- The oxidation number of oxygen in H₂O is -2.
- The oxidation number of sulfur in Na₂SO₄ is +6.
- The oxidation number of phosphorus in P₄ is 0.
- The oxidation number of chlorine in Cl₂ is 0.
- The oxidation number of fluorine in its compounds is always -1.
- The general oxidation number of hydrogen in its compounds is +1, except in metal hydrides where it is -1.
- The general oxidation number of oxygen in oxides is -2, except in peroxides and superoxides.
- The oxidation number of oxygen in peroxides is -1.
- The maximum possible oxidation number of an element in a species is equal to its group number.
- Fluorine is the most electronegative element, with an oxidation number of -1.
- All Group 1A elements (alkali metals) exhibit a +1 oxidation number in their compounds.
- The sum of oxidation numbers of all atoms in a compound is always zero.
Oxidation and Reduction
- Oxidation is the process where the oxidation number of an element increases during a chemical reaction.
- Oxidation and reduction cannot occur independently of each other.
- A substance that oxidizes another substance by getting reduced itself is called an oxidizing agent.
- A substance that reduces another substance by getting oxidized itself is called a reducing agent.
- A chemical reaction where an element present in a single oxidation state at the reactant side converts into two different oxidation numbers at the product side, showing both oxidation and reduction, is called a disproportionation reaction.
- The reverse reaction of disproportionation is called comproportionation.
Redox Reaction Balancing
- Two methods for balancing redox reactions are the half-reaction method and the oxidation number method.
Concentration and Equivalents
- The basic unit of concentration for solutions is molarity (M), which represents moles of solute per liter of solution.
- The n-factor of a substance in redox reactions represents the number of electrons gained or lost per mole of the substance.
- The n-factor of a substance cannot be negative.
- In a chemical reaction, the equivalents of reactants and products are always equal.
Titration
- The process of adding a solution of known concentration (titrant) to a solution of unknown concentration (analyte) until the reaction is complete is called titration.
- The point in a titration when the reaction is complete is called the equivalence point.
- Methods used to determine the strength of a reducing agent include potentiometry and iodometry.
- The process of titrating the excess of a reagent in a reaction with a standard solution is called back titration.
- The point in a titration when an indicator is added to the solution, signaling the completion of the reaction, is called the end point.
- Differential titration involves a process where two different equivalence points are detected by two different indicators.
Water Hardness
- Water containing high concentrations of Ca²⁺ and Mg²⁺ ions is called hard water.
- There are two types of water hardness: temporary hardness (due to bicarbonates of Ca²⁺ and Mg²⁺) and permanent hardness (due to chlorides and sulfates of Ca²⁺ and Mg²⁺).
- The process of removing hardness from water is called water softening.
- Boiling can be used to remove temporary hardness.
- The correct equation for the reaction of Ca(HCO₃)₂ with Na₂CO₃ is: Ca(HCO₃)₂ + Na₂CO₃ → CaCO₃ ↓ + 2NaHCO₃
- The general name for the process of exchanging ions using specific materials to remove hardness is ion exchange.
- Zeolite softening uses sodium zeolite to remove hardness.
- The chemical name for the chemical compound Na₂[Na₄(PO₃)₆] is sodium hexametaphosphate.
- Methods used to remove hardness from water include:
- Boiling (temporary hardness)
- Ion exchange (using zeolite or resins)
- Calgon process (using sodium hexametaphosphate)
- Lime-soda process (using lime and soda ash)
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