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1. Chemical Equations & Reactions Chemical Reaction - Study Questions
1. What is a chemical reaction?
2. What is evidence a reaction has occurred?
3. What is a chemical equation?
4. Define reactants.
5. Define products.
6. Define catalyst.
7. What information is found in an equation?
8. What symbols are used to represent the states of matter?
9. What is the meaning of “aq”?
10. How do you indicate a catalyst is being used in a reaction?
11. What is activation energy?
12. What the three things does conservation of matter require of chemical equations?
13. What is the procedure for balancing a chemical equation?
14. Balance the equation for the reaction of magnesium chloride and silver nitrate to form magnesium nitrate and silver chloride.
15. What is a synthesis reaction?
16. How is a combustion reaction related to a synthesis reaction?
17. What type of reaction is an explosion?
18. Compare decomposition and dissociation.
19. What determines whether one metal will replace another in a single displacement reaction?
20. What is the general form of a double displacement reaction?
21. What type of reaction is each of these?
2Na(s) + Cl2(g) ? 2NaCl(s)
PCl5(s) ? PCl3(s) + Cl2(g)
2Al(s) + Fe2O3(s) ? 2Fe(s) + Al2O3(s)
C6H12O6(s) + 6O2(g) ? 6CO2(g) + 6H2O(l)
BaCl2(aq) + H2SO4(aq) ? 2HCl(aq) + BaSO4(s)
22. What is the oxidation number of an element?
23. What is the oxidation number of the fluorine ion?
24. What is the sum of the oxidation numbers in a compound?
31. Can a redox reaction form a molecule? Explain your answer.
Chemical Reaction - Study Questions
1. What is a chemical reaction?
2. What is evidence a reaction has occurred?
3. What is a chemical equation?
4. Define reactants.
5. Define products.
6. Define catalyst.
7. What information is found in an equation?
8. What symbols are used to represent the states of matter?
9. What is the meaning of “aq”?
10. How do you indicate a catalyst is being used in a reaction?
11. What is activation energy?
12. What the three things does conservation of matter require of chemical equations?
13. What is the procedure for balancing a chemical equation?
14. Balance the equation for the reaction of magnesium chloride and silver nitrate to form magnesium nitrate and silver chloride.
15. What is a synthesis reaction?
16. How is a combustion reaction related to a synthesis reaction?
17. What type of reaction is an explosion?
18. Compare decomposition and dissociation.
19. What determines whether one metal will replace another in a single displacement reaction?
20. What is the general form of a double displacement reaction?
21. What type of reaction is each of these?
2Na(s) + Cl2(g) ? 2NaCl(s)
PCl5(s) ? PCl3(s) + Cl2(g)
2Al(s) + Fe2O3(s) ? 2Fe(s) + Al2O3(s)
C6H12O6(s) + 6O2(g) ? 6CO2(g) + 6H2O(l)
BaCl2(aq) + H2SO4(aq) ? 2HCl(aq) + BaSO4(s)
22. What is the oxidation number of an element?
23. What is the oxidation number of the fluorine ion?
24. What is the sum of the oxidation numbers in a compound?
31. Can a redox reaction form a molecule? Explain your answer.
2. Lecture Outline – Chemical Equations & Reactions
3. Chemical Reactions What you should learn:
In chemical change atoms are rearranged but no atoms are created and none are destroyed
Chemical equations are symbolic representations of what is happening at the molecular level and are used to communicate the conditions under which a reaction proceeds, the products and amount of energy that results, and allow for predictions to be made.
More Specifically...:
Classify those equations that come under the heading of synthesis, decomposition, single replacement, double replacement, neutralization, oxidation/ reduction and combustion
Identify and name acids and bases
Use principle of conservation of mass to balance a reaction
From a written description of a reaction write a balanced reaction using correct state symbols
Show that the conservation of mass is true for a balanced reaction
Predict the products of chemical reactions (including state symbols) when given the reactants.
Use an activity series to predict the spontaneity of reactions.
Use solubility rules to predict the formation of a precipitate
Define oxidation and reduction, and identify any species undergoing oxidation or reduction, and identify the oxidizing and reducing agents
Write half reactions for single replacement reactions (monoatomic ions only)
Fast Track to a 5 (page 61)
To know how to calculate the molecular mass of a covalent compound and the formula mass of an ionic compound
To be able to use the concepts of the mole and molar mass to calculate the number of atoms, molecules, or formula units in a sample of a substance
To be able to determine the empirical formula of a compound from its composition by mass
To know how to derive the molecular formula of a compound from its empirical formula
To be able to describe a chemical reaction
To know how to calculate the quantities of compounds produced or consumed in a chemical reaction
To identify fundamental types of chemical reactions
To begin to predict the types of chemical reactions that substances undergoWhat you should learn:
In chemical change atoms are rearranged but no atoms are created and none are destroyed
Chemical equations are symbolic representations of what is happening at the molecular level and are used to communicate the conditions under which a reaction proceeds, the products and amount of energy that results, and allow for predictions to be made.
More Specifically...:
Classify those equations that come under the heading of synthesis, decomposition, single replacement, double replacement, neutralization, oxidation/ reduction and combustion
Identify and name acids and bases
Use principle of conservation of mass to balance a reaction
From a written description of a reaction write a balanced reaction using correct state symbols
Show that the conservation of mass is true for a balanced reaction
Predict the products of chemical reactions (including state symbols) when given the reactants.
Use an activity series to predict the spontaneity of reactions.
Use solubility rules to predict the formation of a precipitate
Define oxidation and reduction, and identify any species undergoing oxidation or reduction, and identify the oxidizing and reducing agents
Write half reactions for single replacement reactions (monoatomic ions only)
Fast Track to a 5 (page 61)
To know how to calculate the molecular mass of a covalent compound and the formula mass of an ionic compound
To be able to use the concepts of the mole and molar mass to calculate the number of atoms, molecules, or formula units in a sample of a substance
To be able to determine the empirical formula of a compound from its composition by mass
To know how to derive the molecular formula of a compound from its empirical formula
To be able to describe a chemical reaction
To know how to calculate the quantities of compounds produced or consumed in a chemical reaction
To identify fundamental types of chemical reactions
To begin to predict the types of chemical reactions that substances undergo
4. Organize Your Thoughts To identify the reactants and products in a chemical equation.
To balance a chemical equation with coefficients.
To identify synthesis (combination), decomposition, and combustion reactions.
To identify single-replacement reactions.
To identify double-replacement reactions.
To predict the products of a reaction.To identify the reactants and products in a chemical equation.
To balance a chemical equation with coefficients.
To identify synthesis (combination), decomposition, and combustion reactions.
To identify single-replacement reactions.
To identify double-replacement reactions.
To predict the products of a reaction.
5. Describing a Chemical Reaction Indications of a Chemical Reaction
Evolution of heat, light, and/or sound
Production of a gas
Formation of a precipitate
Color change Objective:
To state four observations that are evidence for a chemical reaction.
Photo of precipitate: http://www.geocities.com/chem_reactions/Images/Precipitate.jpgObjective:
To state four observations that are evidence for a chemical reaction.
Photo of precipitate: http://www.geocities.com/chem_reactions/Images/Precipitate.jpg
6. Signs of Chemical Reactions
7. Chemical Equations A chemical equation is an expression that gives the identities and quantities of the substances in a chemical reaction
Chemical formulas and other symbols are used to indicate the starting material(s) or reactant(s), which are written on the left side of the equation, and the final compound(s) or product(s), which are written on the right side. An arrow, read as yields or reacts to form, points from the reactants to the products.
Abbreviations are added in parentheses as subscripts to indicate the physical state of each species:—(s) for solid, (l) for liquid, (g) for gas, and (aq) for an aqueous solution.
A balanced chemical equation is when both the numbers of each type of atom and the total charge are the same on both sides. A chemical reaction represents a change in the distribution of atoms but not in the number of atoms.
http://img.alibaba.com/photo/10784694/Aluminum_Oxide_Abrasive_Fine_Grit_120_220_.jpg
http://upload.wikimedia.org/wikipedia/commons/thumb/f/f2/Corundum_Aluminum_Oxide_Gallantin_Co_MontanaDSC03201.jpg/600px-Corundum_Aluminum_Oxide_Gallantin_Co_MontanaDSC03201.jpg
http://www.germes-online.com/direct/dbimage/50327532/Aluminum_Alloy_Pipe.jpgA chemical equation is an expression that gives the identities and quantities of the substances in a chemical reaction
Chemical formulas and other symbols are used to indicate the starting material(s) or reactant(s), which are written on the left side of the equation, and the final compound(s) or product(s), which are written on the right side. An arrow, read as yields or reacts to form, points from the reactants to the products.
Abbreviations are added in parentheses as subscripts to indicate the physical state of each species:—(s) for solid, (l) for liquid, (g) for gas, and (aq) for an aqueous solution.
A balanced chemical equation is when both the numbers of each type of atom and the total charge are the same on both sides. A chemical reaction represents a change in the distribution of atoms but not in the number of atoms.
http://img.alibaba.com/photo/10784694/Aluminum_Oxide_Abrasive_Fine_Grit_120_220_.jpg
http://upload.wikimedia.org/wikipedia/commons/thumb/f/f2/Corundum_Aluminum_Oxide_Gallantin_Co_MontanaDSC03201.jpg/600px-Corundum_Aluminum_Oxide_Gallantin_Co_MontanaDSC03201.jpg
http://www.germes-online.com/direct/dbimage/50327532/Aluminum_Alloy_Pipe.jpg
8. Chemical Equations
9. Chemical Equations
10. Chemical Equations
11. Characteristics of Chemical Equations The equation must represent known facts.
The equation must contain the correct formulas for the reactants and products.
The law of conservation of mass must be satisfied.
12. Chemical Equations Reactants – the substances that exist before a chemical change (or reaction) takes place.
Products – the new substance(s) that are formed during the chemical changes.
CHEMICAL EQUATION indicates the reactants and products of a reaction.
Objectives:
To identify seven elements that occur naturally as diatomic molecules, H2, N2, O2, F2, Cl2, Br2, I2. [HOBrFINCL twins or BrINClHOF brothers]
To write a chemical equation from the description of a chemical reaction.Objectives:
To identify seven elements that occur naturally as diatomic molecules, H2, N2, O2, F2, Cl2, Br2, I2. [HOBrFINCL twins or BrINClHOF brothers]
To write a chemical equation from the description of a chemical reaction.
13. Word Equations A WORD EQUATION describes chemical change using the names of the reactants and products.
15. Visualizing a Chemical Reaction
16. Visualizing a Chemical Reaction
17. Meaning of Chemical Formula
18. Balancing Chemical Equations Balanced Equation – one in which the number of atoms of each element as a reactant is equal to the number of atoms of that element as a product
Objective:
To write balanced chemical equations by inspection.
Balanced chemical equation
– Provides qualitative information about the identities and physical states of the reactants and products
– Provides quantitative information because it tells the relative amounts of reactants and products consumed or produced in the reaction
– The number of atoms, molecules, or formula units of a reactant or product in a balanced chemical equation is the coefficient of that species
– Mole ratio of two substances in a chemical reaction is the ratio of their coefficients in the balanced chemical equation
Objective:
To write balanced chemical equations by inspection.
Balanced chemical equation
– Provides qualitative information about the identities and physical states of the reactants and products
– Provides quantitative information because it tells the relative amounts of reactants and products consumed or produced in the reaction
– The number of atoms, molecules, or formula units of a reactant or product in a balanced chemical equation is the coefficient of that species
– Mole ratio of two substances in a chemical reaction is the ratio of their coefficients in the balanced chemical equation
19. Balancing Chemical Equations Write a word equation for the reaction.
Write the correct formulas for all reactants and products.
Determine the coefficients that make the equation balance.
20. Method for balancing chemical equations
1. Identify the most complex substance.
2. Beginning with that substance, choose an element that appears in only one reactant and one product. Adjust the coefficients to obtain the same number of atoms of this element on both sides.
3. Balance polyatomic ions (if present) as a unit.
4. Balance the remaining atoms, usually ending with the least- complex substance and using fractional coefficients if necessary. If a fractional coefficient is used, multiply both sides of the equation by the denominator to obtain whole numbers for the coefficients.
5. Count the numbers of atoms of each kind on both sides of the equation to be sure that the chemical equation is balanced.
Method for balancing chemical equations
1. Identify the most complex substance.
2. Beginning with that substance, choose an element that appears in only one reactant and one product. Adjust the coefficients to obtain the same number of atoms of this element on both sides.
3. Balance polyatomic ions (if present) as a unit.
4. Balance the remaining atoms, usually ending with the least- complex substance and using fractional coefficients if necessary. If a fractional coefficient is used, multiply both sides of the equation by the denominator to obtain whole numbers for the coefficients.
5. Count the numbers of atoms of each kind on both sides of the equation to be sure that the chemical equation is balanced.
22. Balancing Chemical Equations
23. 1) Write a word equation for the reaction.
25. CH4 + 2 O2 ? CO2 + 2 H2O
26. Reactants ? Products
27. Showing Phases in Chemical Equations Solid Phase – the substance is relatively rigid and has a definite volume and shape. NaCl(s)
Liquid Phase – the substance has a definite volume, but is able to change shape by flowing. H2O(l)
Gaseous Phase – the substance has no definite volume or shape, and it shows little response to gravity. Cl2(g)
28. Additional Symbols Used in Chemical Equations “Yields”; indicates result of reaction
Used to indicate a reversible reaction
A reactant or product in the solid state;
also used to indicate a precipitate
Alternative to (s), but used only to indicate a precipitate
A reactant or product in the liquid state
A reactant or product in an aqueous solution
(dissolved in water)
A reactant or product in the gaseous state
