Bellringer 9/20

1. How many protons does mercury have? Electrons? Neutrons?

2. Which subatomic particle determines the kind of element?

3. Which subatomic particles determine a element’s chemical properties?

4. What are valence electrons?

Bellringer 9/21

1. What is a saturated solution?2. How are unsaturated solutions different from

supersaturated solutions?3. What are 3 ways to speed up the rate of

dissolving a solute in a solvent?

Core Concepts 1&2Solutions

• A homogeneous mixture of two or more substances.• Can be separated by physical means.• Can occur in the solid, liquid, or gas phase.• Solute – the part of the solution that is dissolved

and usually present in the lesser amount. (salt-solute, water-solvent)

• Solvent – the part of the solution doing the dissolving and usually present in the greater amount.

• Solutions are classified as unsaturated, saturated, and supersaturated.

• A saturate solution has the maximum dissolved solute for the amount of solvent used at a specific temperature and pressure.

• Electrolyte – an aqueous solution that conducts electricity. Pure water does not conduct electricity well.

• Aqueous solution – solution where water is the solvent. Water is a polar solvent. That means it is a molecule which has a (+) and (-) side.

• Like dissolves like – This means that a solute will dissolve best in a solvent that has the same or similar polarity.

• Solubility and Temperature Gizmo | ExploreLearning

Factors that affect dissolving rate

1. Surface area – greater surface area dissolves faster.

2. Higher temperatures dissolve faster because the particles move faster.

3. Stirring dissolve faster because the particles spread out faster in the solvent.

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Bellringer 9/22

1. Why does stirring increase the dissolving rate of a solute in a solvent?

2. Why does heating increase the dissolving rate of a solute in a solvent?

3. Why does increasing surface area of a solute increase the dissolving rate? List one way to increase the surface area of a solute.

Solutions

• Concentration – the quantity of solute dissolved in a certain amount of solvent. Concentrated has a large amount of solute – diluted has a small amount.

• Concentration is expressed as molarity or moles per liter of solution.

Bellringer 9/23

A solution of sodium sulfide (Na2S) has a solubility of 26.3g/100g of H2O at 200C.

1. What is this solution know as?2. About how much sodium sulfide would be needed for

the solution to be unsaturated?3. About how much would be need to be supersaturated?4. If the temperature was raised to 600C, would you

expect more or less than 26.3g to dissolve in the 100g of water?

Ionic and Covalent Bonding

• Bonded atoms form many kinds of substance. Example: sodium (Na) and chlorine (Cl) bond to form NaCl (table salt).

• Atoms bond when their valence electrons interact.

• Atoms join to form bonds so that each atom has a stable electron configuration like those of the Noble Gases.

Ionic Bonding

• Formed between oppositely charged ions.• An ion is a charged atom with either more or

less electrons than protons.• Formed by the transfer of electrons. Example:

sodium (Na) transfers its one valence electron to chlorine (Cl) so that Na now has 8 outer level electrons and Cl with 7 before the transfer, has 8 outer electrons. Na is now positive (+) or cation, and Cl negative (-) anion.

• Calcium can combine with chlorine to form calcium chloride. Calcium (Ca+2) has 2 valence electrons and so it takes 2 chlorine ions (Cl-) to balance with it. Cl- + Ca+2 + Cl- The chemical formula is CaCl2.

• Electron dot diagrams.• Electron Dot Diagram – YouTubeDraw electron dot diagrams for the following

elements: Na, Ca, O, F, Ne, Kr, Al, and N. Will they be cations or anions?

Writing formulas for Ionic Compounds

What is the chemical formula for aluminum fluoride?Look up symbol for aluminum ion:

Al+3

Look up symbol for fluoride ion: F-

Al+3 F-

It will take 3(-) to balance with +3 or 3F to balance with 1 Al.

AlF3

Write the chemical formula for the following:

1. Iron (II) Iodide (hint: the roman numeral indicates the cation’s charge)

2. Potassium Nitrate3. Aluminum Chloride4. Magnesium Oxide5. Lithium Sulfide6. Titanium (IV) oxide

Dot Diagrams of Selected Elements

Formulas Lesson 3: Transition Metals Part 1 – YouTubeFormulas Lesson 4: Transition Metals Part 2 - YouTube

Polyatomic ions

• Ions made up of 2 or more atoms.• They act the same as elemental ions.Example: (NH4)+ is the ammonium ion. (NO3)- is

the nitrate ion. Since one is + and the other is (-) then ammonium nitrate’s chemical formula is NH4NO3

• Anions end in –ite or –ate for most of them.

.Polyatomic Ion Charge = +1ammonium - NH4

+

Polyatomic Ion Charge = -1acetate - C2H3O2

-

bicarbonate (or hydrogen carbonate) - HCO3-

bisulfate (or hydrogen sulfate) - HSO4-

chlorate - ClO3-

chlorite - ClO2-

cyanate - OCN-

cyanide - CN-

dihydrogen phosphate - H2PO4-

hydroxide - OH-

nitrate - NO3-

nitrite - NO2-

perchlorate - ClO4-

permanganate - MnO4-

thiocyanate - SCN-

Polyatomic Ion Charge = -2carbonate - CO3

2-

chromate - CrO42-

dichromate - Cr2O72-

hydrogen phosphate - HPO42-

peroxide - O22-

sulfate - SO42-

sulfite - SO32-

thiosulfate - S2O32-

Polyatomic Ion Charge = -3borate - BO3

3-

phosphate - PO43-

Using the chart to write chemical formulas.

Example: What is the chemical formula for sodium hydroxide?

Na+ is paired with (OH)-. Since they both have a single charge then combine them and drop the signs. NaOH

Example: ammonium sulfate?Ammonium is (NH4)+ and sulfate is (SO4)-2. It takes 2

(NH4)+ to pair with one (SO4)-2.The formula is (NH4)2SO4. Notice that there are 2N and

2H4 so counting atoms there are

(NH4)2SO4

8 – hydrogen (H) atoms2 – nitrogen (N) atoms

1 – sulfur (S) atom4 – oxygen (O) atoms

Naming and Formulas of SOME Polyatomic Ions: Chemistry Lesson - YouTube

Write the chemical formulas for the following: Use the chart on page 158 and the periodic table.

1. hydrogen phosphate2. hydrogen carbonate3. Potassium hydroxide4. Calcium chlorate5. Calcium carbonate6. Sodium phosphate7. Sodium cyanide8. Aluminum sulfate

Chemical Reactions

• Chemical reactions change substances.• Reactants – the substances that are used in the

chemical reactions.• Products – the new substances formed from the

reactants in the chemical reactions.• Endothermic reaction – reactions that absorb

energy during the reaction. (Cold packs)• Exothermic reaction – reaction that releases

energy during the reaction. (heat packs)

Classifying Reactions

• Synthesis reactions – reactions where two or more substances combine to form a new compound. 2Na + Cl2 2NaCl (notice that 2 Na on both sides of arrow and 2 Cl also)

• Decomposition reaction – a reaction where a compound breaks apart into 2 or more substances. 2H20 2H2 + 02

Chemical Reactions

• Combustion reaction – The oxidation reaction of an organic compound in which heat is released.

2CH4 + 4O2 2CO2 + 4H2OMethane gas reacting with oxygen producing

carbon dioxide and water.

Chemical reactions

• Single-displacement reaction – A reaction in which one element or radical takes the place of another element or radical in a compound.

3CuCl2 + 2Al 2AlCl3 + 3CuCopper is replaced with aluminum

A more reactive element takes the place of a less reactive one.

A radical is an organic group that has one or more electrons available for bonding.

Chemical reactions

• Double-displacement reactions – a reaction in which a gas, a solid precipitate, or a molecular compound forms from an apparent exchange of atoms or ions between two compounds.

Pb(NO3)2 + K2CrO4 PbCrO4 + 2KNO3

Lead nitrate reacting with potassium chromate to produce lead chromate and potassium nitrate.

Chemical Reactions

• Oxidation-reduction reaction – any chemical change in which one species is oxidized (loses electrons) and another species in reduced (gains electrons). Referred to as redox reaction.

Respiration (breathing) is a redox reaction. Oxygen gas reacts with carbon compounds to form carbon dioxide. Carbon atoms in CO2 are oxidized (lose electrons) and Oxygen atoms are reduced (gain electrons).

Elements_of_Chemistry__Compounds_and_Reactions.asf

Classify the following reactions

1. La2O3 + H2O La(OH)3

2. NH4NO3 N2O + H2O3. C3H8 + O2 CO2 + H2O4. Mg + HCl MgCl2 + H2

5. Mg(OH)2 + HCl MgCl2 + H2OPut yes behind those equations that are

balanced.

Bell RingerIdentify the following reactions

1. CaSO4 + Mg(OH)2 --> Ca(OH)2 + MgSO4 2. Cl2O5 Cl2 + O2

3. Al + Fe2O3 Al2 O3 + Fe4. H2 + N2 NH3

SynthesisDecomposition

Single-displacementDouble replacement

Balancing Chemical Equations

Mg + HCl MgCl2 + H2

Is this equation balanced?No since there are 2 Hs and 2 Cls on the right

side and only one each on the left side.Suppose we put a 2 in front of HCl.

Mg + 2HCl MgCl2 + H2

Is it now balanced?

Balance these equations1) ____ N2 + ____ H2 ____ NH3

2) ____ KClO3 ____ KCl + ____ O2

3) ____ NaCl + ____ F2 ____ NaF + ____ Cl2

4) ____ H2 + ____ O2 ____ H2O 5) ____ Pb(OH)2 + ____ HCl ____ H2O + ____ PbCl2

6) ____ AlBr3 + ____ K2SO4 ____ KBr + ____ Al2(SO4)3

7) ____ CH4 + ____ O2 ____ CO2 + ____ H2O 8) ____ C3H8 + ____ O2 ____ CO2 + ____ H2O

Check your work1) 1 N2 + 3 H2 2 NH3

2) 2 KClO3 2 KCl + 3 O2

3) 2 NaCl + 1 F2 2 NaF + 1 Cl2

4) 2 H2 + 1 O2 2 H2O 5) 1 Pb(OH)2 + 2 HCl 2 H2O + 1 PbCl2

6) 2 AlBr3 + 3 K2SO4 6 KBr + 1 Al2(SO4)3

7) 1 CH4 + 2 O2 1 CO2 + 2 H2O 8) 1 C3H8 + 5 O2 3 CO2 + 4 H2O