1.Compare the number of electrons in an ion of Na to an atom of Na. 2.Explain, in terms of electrons and energy, how ions emit light. 3.Explain, in terms of electrons, why the noble gases are non- reactive. 4.Define orbital. Name: ______________ Do Now 3/18/13

1.Compare the number of electrons in an ion of Na to an atom of Na. 2.Explain, in terms of electrons and energy, how ions emit light. 3.Explain, in terms of electrons, why the noble gases are non- reactive. 4.Define orbital. Name: ______________ Do Now 3/18/13

Chemical Equations NOTES When reactants are converted into products, a chemical reaction has occurred. When a reaction is represented by symbols, it is called a chemical equation. In chemistry we represent the equal sign as an arrow. The materials we start with are the reactants. The arrow represents the reaction or what is yielded. The materials that are made from a reaction are called the products.

Equations 6 + x = 14 C + O 2  CO 2

Reactants Products Yields or Produces 1 C Atom + 2 O Atoms = 1 C Atom + 2 O Atoms NOTES

Law of Conservation of Matter (or Mass) Matter cannot be created nor destroyed under ordinary chemical reactions. Atoms cannot be created nor destroyed in a chemical equation. NOTES

H 2 + O 2  H 2 O

Rules for Balancing Equations You cannot change formulas or subscripts Balancing atoms NOT molecules Can only add coefficients in front of formulas H 2 + N 2  NH 3 NOTES

H 2 + N 2  NH 3 H 2 + N 2  2NH

3H 2 + N 2  2NH 3 6 Atoms of H 2 Atoms of N 2 Atoms of N 6 Atoms of H NOTES 3 Molecules of Hydrogen 1 Molecule of Nitrogen 2 Molecules of Ammonia ≠ Not Balancing Molecules

Balancing Chemical Equations NOTES Balance one element (or ion) at a time Have a system Check everything again when you’re done balancing

C + Cl 2  CCl 4 NOTES

CO + H 2  CH 3 OH NOTES

CS 2 + O 2  CO 2 + SO 2 NOTES

CaCl 2 + Cr(NO 3 ) 3  Ca(NO 3 ) 2 + CrCl 3 NOTES

Naming  Remember, the positive ion always comes first followed by the negative ion  When it is just the negative ion alone, the name ends in –ide  NaCl  Sodium Chloride  If the name ends in something other than –ide, check your reference table

Naming  Once you have the two pieces that are involved in the compound, determine their charges (from the periodic table) and CRISS CROSS Lithium Phosphide LiP +1-3 Li 3 P

Things to Remember: Formulas First Roman Numerals tell you the charge of the ion Criss-Cross oxidation states for subscripts Diatomic Elements (I 2, Br 2, Cl 2, F 2, O 2, N 2, H 2 ) these are never just one atom Balance the equation with Coefficients Hydrogen reacts with Chlorine to make Hydrogen Chloride. H 2 + Cl 2  HCl2 NOTES

Zinc + Silver Nitrate yields Zinc Nitrate + Silver Write correct formulas (subscripts) and balance the following equations (coefficients) NOTES

Barium Chloride + Sodium Sulfate yields Barium Sulfate + Sodium Chloride

Mr. Marbley mixes a sample of copper with a sample of sulfur in a beaker. The product is determined to be copper (I) sulfide.

Mr. Abdalla mixes a sample of copper with a sample of sulfur in a beaker. The product is determined to be copper (I) sulfide.

Mr. Williams mixes a sample of copper with a sample of sulfur in a beaker. The product is determined to be copper (I) sulfide.

Mr. Howell mixes a sample of copper with a sample of sulfur in a beaker. The product is determined to be copper (I) sulfide.

Today’s Agenda 1.Do Now (5 minutes) a.Gather papers b.Hand in homework c.Try the regents problems 2. Mini Lessons: a. One half of class will do reactions lab b. Rest of class will do interval reflection c. SWITCH 3.Types of Chemical Reactions a.Notes b.Combustion Demonstration

Lab Procedure 1.Place ONE tablet in the balloon. 2.Crush the tablet up. 3.Fill the flask with 100 mL of warm water. 4.Place the balloon on the top of the flask. DO NOT dump the contents of the balloon into the flask. 5.Find the mass of the flask, water, balloon, and tablet. 6.Leaving the set-up on the scale, tip the balloon up so the tablet falls into the water. 7.Once the reaction stops, find the final mass of the set-up.

Types of Chemical Reactions Gives you the ability to predict what the products will be when you mix two reactants NOTES

Combustion A hydrocarbon + O 2  CO 2 + H 2 O 2CH 4 + 4O 2  2CO 2 + 4H 2 O NOTES

Balancing Combustion Reactions C 2 H 6 + O 2  CO 2 + H 2 O NOTES Always balance Oxygen LAST

Synthesis NOTES 2 or more substances combine to form a more complex substance A + B  AB

Putting Puzzle Pieces Together Synthesis Reaction

Fe + S  FeS 2Mg + O 2  H 2 O + SO 3  H 2 SO 4 2MgO

Solving Synthesis Reactions

Formula Writing  In ionic bonds, an electron is transferred between the atoms.  Example: Na Cl +1+1

Formula Writing We can get the charge of an atom by looking at the periodic table.

What is the charge of a phosphorous ion? What is the charge of a magnesium ion? What are the charges of the ions Lithium and Fluorine?

Formula Writing Once we have the charges, we crisscross the numbers to the subscript position. NaCl +1+1

Formula Writing So the final formula for sodium and chlorine is just NaCl

What is the formula for Na and Br? What is the formula for Mg and Cl? What is the formula for Rh and O?

Solving Equations  So now we can write formulas  We can identify synthesis reactions  Lets put it all together. H  ????

Solving Equations H  Step 1: Look up the oxidation states for each element on the periodic table.

Solving Equations H  Step 2:Crisscross

Solving Equations H  Step 3: Rewrite

Solving Equations H  Step 4: Balance the Equation H2OH2O

Solve the following equation Na + F 2  ???

Solve the following equation H 2 + P  ???

Solve the following equation Sr + N  ???

NOTES Decomposition 1 substance breaks down into 2 or more simpler substances AB  A + B

Breaking Apart a Puzzle Decomposition Reaction

FeS  Fe + S 2NaCl  CaCO 3  CaO + CO 2 2Na + Cl 2

Decomposition Reactions Decomposition reactions are the same as synthesis reactions, only in reverse. 2H 2 + O 2  2H 2 O 2H 2 O  2H 2 + O 2

Diatomic Atoms  When breaking a compound apart, you must remember that not all elements stay alone.  Elements that naturally bond with themselves are called Diatomic H2H2 O2O2 N2N2 Br 2 I2I2 F2F2 Cl 2 I 2 Br 2 ing Cl 2 ay F 2 rom O 2 ur N 2 ew H 2 ouse

Decomposition Reactions NaCl  SrF 2 

Practice: Complete the following decomposition reactions 1. MgBr 2  2. Na 2 O  3. HCl 

NOTES Single Replacement 1 substance in a compound replaces another. An element reacts with a compound. AB + C  AC + B AB + C  CB + A

Sharing among Children Single Replacement Reaction

Why do single replacement reactions occur? A more reactive element replaces a less reactive element NOTES

Zn + 2HCl  ZnCl 2 + H 2 2Na + CuSO 4  Na 2 SO 4 + Cu Cl 2 + 2KBr  2KCl + Br 2

Single Replacement Reactions In a single replacement reaction, one element replaces another in a compound. Sr + 2HCl  H 2 + SrCl 2

Formulas Remember, the first element in a compound’s formula is the cation (positively charged ion). The second element in a compound’s formula is the anion (negatively charged ion)

Who to Replace? Step 1: What is the potential charge on the single element? Step 2: Which element in the compound has the same type of charge? Be + NaCl  BeCl 2 + Na

Complete the following reaction: Li + NaCl  Complete the following reaction: O 2 + NaCl 

But will it happen? In order for one element to replace another, it must be higher on Table J than

Check Your Homework… Any Questions? 5. 2Na + 2HOH  H 2 + 2NaOH 6. B + 3KF  3K + BF 3 7. Ba + BaS  Ba + BaS 8. Ca + 2HOH  H 2 + Ca(OH) 2

NOTES Double Replacement 2 substances in a compound “switch” partners. A compound reacts with a compound. AB + CD  AD + CB

Trading Double Replacement Reaction

Why do double replacement reactions occur? One of the products must form as a gas, a precipitate or as water NOTES

Also known as… ionic reaction or solution reaction

NaCl + AgNO 3  NaNO 3 + AgCl 2K 3 PO 4 + 3CaS  Ca 3 (PO 4 ) 2 + 3K 2 S

Double Replacement Reactions  In a double replacement reaction, two ions switch places in two compounds. NaFLiCl

Double Replacement Reactions Once you have identified which two will switch (by looking at the charges), complete the switch and rewrite the formula. NaN+Mg O  3

Double Replacement Reactions KF + SrO 

Practice: NaCl + BeF 2

Practice: MgO + KCl

Practice: BaBr 2 + K 2 O

Polyatomic Ions Polyatomic Ions are multinuclear ions that can be treated as a group of atoms with a charge.

KCNSr SO ( )

Complete: Ba(NO 3 ) 2 + K 2 C 2 O 4

Complete: NaHCO 3 + HCl

Using Balanced Equations

What we know…  Balanced equations follow the law of conservation of mass (whatever I start with I have to end with)  In order to balance an equation, we place coefficients in front of the formulas  Formulas represent groupings of atoms that are bonded together

Using Ratios  Consider the ratio 2 leaves : 1 plant If I have 3 plants, how many leaves do I have? 2 leaves 1 plant X leaves 3 plants =

Equations as Ratios  Consider the following: H 2 + Cl 2  2HCl One Molecule of Hydrogen One Molecule of Chlorine Two Molecules of Hydrogen Chloride There is a ratio between molecules 1 : 1 : 2

Equations as Ratios 1H 2 + 1Cl 2  2HCl How many HCl would be made if I used 3 molecules of Cl 2 ?

Equations as Ratios 1H 2 + 1Cl 2  2HCl How many H 2 would be needed if I made 8 molecules of HCl?

Mole Ratios  The coefficients of balanced equations also represent moles.  What is a mole?  A mole is a number of particles just like a dozen is 12 particles. 1H 2 + 1Cl 2  2HCl 1 mole = x particles

Mole-Mole Problems Instead of talking about molecules, we simply switch to thinking about moles.

How many moles of Cl 2 is needed to make 10 moles of HCl? 1H 2 + 1Cl 2  2HCl

How many moles of HCl can be made using 6 moles of H 2 ? 1H 2 + 1Cl 2  2HCl

How many moles of Cl 2 are used in the production of 4 moles of HCl? 1H 2 + 1Cl 2  2HCl

How many moles of HCl would be made if I used 3 moles of Cl 2 ?

Consider: 3H 2 + N 2  2NH 3 How many moles of NH 3 are made from 6 moles of H 2 ?

Consider: 3H 2 + N 2  2NH 3 How many moles of N2 are used with 9 moles of H 2 ?

Molar Mass

What we know…  Balanced equations follow the Law of Conservation of Mass  Equations can represent the ratio of molecules or moles involved in a reaction  A mole is a number of particles (6.022 x )

Measuring Moles  We do not have an instrument that measures the number of moles of a substance.  Instead of measuring moles, we can measure mass and convert to moles 3 Moles of H 2 O 48 grams of H 2 O

Molar Mass  The atomic mass unit was developed using our understanding of a mole.  Therefore, the molecular mass of a molecule in amu is equal to its molar mass in grams. 0 H2OH2O 1 x 16 amu 2 x 1 amu = 16 amu = 2 amu 18 amu + 18 grams 1 Mole…

What is the molar mass of CH 4 ?

What is the molar mass of NO 2 ?

Using Molar Mass  There are times when we want to know how many particles are involved in a reaction  By using the molar mass, we can convert between moles (a number of particles) and mass.

Converting Moles to Grams  The mass of one mole of a substance is known as its molar mass  We can convert moles to grams using the formula Moles = grams gram formula mass

How many grams does 2 moles of CO 2 weigh?

How much does 3 moles of H 2 O weigh?

Converting Mass to Moles  In order to convert between mass and moles, we can use the same formula as before. How many moles is 36 grams of water?

How many moles is 48 grams of H 2 O?

How many moles is 90 grams of H 2 O?

Collision Theory

What we know…  A reaction is when elements or compounds interact to produce new combinations of elements and compounds.  Reactions occur when molecules collide (sometimes…)  Rate is another way of saying “how fast” something changes

Collision Theory  Consider the reaction CO(g) + NO 2 (g)  CO 2 (g) + NO(g)  In order for a reaction to occur, the carbon monoxide and nitrogen dioxide gas particles need to come together  But it is more than just coming together, they need to have specific conditions

Collision Theory In order for a reaction to occur, the two particles need to come together with the correct amount of energy and the correct orientation.

Collision Theory Correct Energy : Particles need to collide with enough energy to overcome the activation energy of the reaction Correct Orientation : Particles need to collide with the correct positioning to allow for the correct bonds to be made.

Ways to Increase Rate  There are four means to which the rate of a reaction can be increased:  Nature of the Reactants (some are more reactive)  Concentration (the amount of particles in solution)  Surface area (the number of particles available to react)  Temperature (how fast the particles are moving)

Nature of Reactants  Consider Table J, some elements are more reactive than others  This can be due to the…  Electronegativity (how much it wants the electron in a bond)  Electron Configuration (how close it is to achieving a stable 8)  Ionization Energy (how hard it is to remove the electron)

Concentration  As the number of particles increases, the chance of an effective collision increases  Just like cars on a road, the more cars there are, the better the chance is to get into an accident

Surface Area  The more substance that is exposed to collisions, the faster (more collisions) the reaction will go  Surface area is increased by… grinding, breaking up, crushing, stirring, shaking, swishing…

Temperature  Temperature is a measure of the particle movement  As we increase temperature, we increase movement and increase the number of collisions  For many reactions an increase in temperature increases the rate of the reaction

LeChatelier’s Principle

What we must know…  A system is at equilibrium when the rates of change are equal  When a stress is applied to the system, the system will rebalance.  When concentration is changed, the system will shift to use up the added material

LeChatelier’s Principle 3H 2 + N 2  2NH 3 By adding more H 2, we have more collisions between H 2 and N 2 More collisions drives the reaction forward

LeChatelier’s Principle 3H 2 + N 2  2NH 3 By adding more NH 3, we have more chances for decomposition More decomposition drives the reaction in reverse

CH 4 + 2O 2  2H 2 O + CO 2 an increase in H 2 O will… 1.Shift the reaction left 2.Shift the reaction right 3.Cause no change

What could be done to shift the following reaction to the left? H 2 + I 2  2HI 1.Increase the concentration of I 2 2.Increase the concentration of H 2 3.Decrease the concentration of HI 4.Increase the concentration of HI

CH 4 + 2O 2  2H 2 O + CO 2 an increase in oxygen will… 1.Cause the reaction to shift left with the production of H 2 O 2.Cause the reaction to shift left with the production of CH 4 3.Cause the reaction to shift right with the production of H 2 O 4.Cause the reaction to shift right with the production of CH 4

Changes in Pressure/Volume  When we increase the pressure or decrease the volume, we push the particles closer together  This results in more collisions

Changes in Pressure/Volume 3H 2 + N 2  2NH 3 A decrease in pressure will cause the system to shift towards the side with more molecules

Coefficients as Moles  Remember, the coefficients of the equation represent a mole ratio of molecules and atoms. 2C 2 H 6 + 7O 2  6H 2 O + 4CO 2 Which side has more moles of gas?

Consider:2C 2 H 6 + 7O 2  6H 2 O + 4CO 2 if the pressure is increased… 1.The reaction will shift towards the left 2.The reaction will shift towards the right

Consider:2C 2 H 6 + 7O 2  6H 2 O + 4CO 2 if the volume is increased… 1.The reaction will shift towards the left 2.The reaction will shift towards the right

Consider: 2H 2 + O 2  2H 2 O If the pressure is decreased 1.The reaction will shift to the left 2.The reaction will shift to the right

Consider: 2H 2 + O 2  2H 2 O If the volume is increased 1.The reaction will shift to the left 2.The reaction will shift to the right

Changes in Temperature  Exothermic Reaction is when energy is given off  and Endothermic Reaction is when energy is absorbed  We can include the heat in a chemical reaction Heat + A + B  C + D or A + B  C + D + Heat EndothermicExothermic

Changes in Temperature  In an equilibrium system, if the forward reaction is exothermic, the reverse reaction will be the opposite, endothermic 2H 2 + O 2  2H 2 O + Heat Exothermic Endothermi c

Changes in Temperature  If we add heat to the system, are we helping the endothermic or exothermic reaction? 2H 2 + O 2  2H 2 O + Heat Adding heat favors the endothermic reaction The reverse reaction is favored. Reaction shifts to the left.

Changes in Temperature  By removing heat from the system (cooling it down) we favor the exothermic reaction. Heat + CuCO3  CuO + CO 2 Exothermic

If the following system was cooled, the equilibrium will… 2H 2 + O 2  2H 2 O + Heat 1.Shift in the forward direction 2.Shift in the reverse direction

Adding heat to the following reaction will… Heat + 2HI  H 2 + I 2 1.Shift to the left, favoring the exothermic reaction 2.Shift to the right favoring the exothermic reaction 3.Shift to the left favoring the endothermic reaction 4.Shift to the right favoring the endothermic reaction

In Summary

Molar Mass

What we know…  Balanced equations follow the Law of Conservation of Mass  Equations can represent the ratio of molecules or moles involved in a reaction  A mole is a number of particles (6.022 x )

Measuring Moles  We do not have an instrument that measures the number of moles of a substance.  Instead of measuring moles, we can measure mass and convert to moles 3 Moles of H 2 O 48 grams of H 2 O

Molar Mass  The atomic mass unit was developed using our understanding of a mole.  Therefore, the molecular mass of a molecule in amu is equal to its molar mass in grams. H2OH2O 1 x 16 amu 2 x 1 amu = 16 amu = 2 amu 18 amu + 18 grams 1 Mole…

What is the molar mass of CH 4 ?

What is the molar mass of NO 2 ?

Using Molar Mass  There are times when we want to know how many particles are involved in a reaction  By using the molar mass, we can convert between moles (a number of particles) and mass.

Converting Moles to Grams  The mass of one mole of a substance is known as its molar mass  We can convert moles to grams using the formula Moles = grams gram formula mass

How many grams does 2 moles of CO 2 weigh?

How much does 3 moles of H 2 O weigh?

Converting Mass to Moles  In order to convert between mass and moles, we can use the same formula as before. How many moles is 36 grams of water?

How many moles is 48 grams of H 2 O?

How many moles is 90 grams of H 2 O?