Unit 3 - Chemical Bonding Answers PDF

## Physical and Chemical Changes ### Starter Activity Sort these reactions into chemical or physical changes by drawing a line to the correct heading. [4] - dissolving sugar - physical change - baking a cake - chemical change - boiling water - physical change - burning toast - chemical change -...

## Physical and Chemical Changes ### Starter Activity Sort these reactions into chemical or physical changes by drawing a line to the correct heading. [4] - dissolving sugar - physical change - baking a cake - chemical change - boiling water - physical change - burning toast - chemical change - frying an egg - chemical change - melting chocolate - physical change - freezing milk - physical change - popping corn - chemical change ### How can you tell if a reaction is a chemical or a physical change? [1] ### Lab Investigation: Physical and Chemical Change Stations | Station Number | Physical/Chemical Change | Evidence | |---|---|---| | 1 | Physical | Can be reversed | | 2 | Chemical | Bubble Formation | | 3 | Chemical | Explosion | | 4 | Chemical | pH Changes | | 5 | Physical | Change in State | | 6 | Physical | Can be separated | ## Read each scenario below. Decide whether a physical or chemical change has occurred and give evidence for your decision. The first one has been done for you as an example. | Scenario | Physical or Chemical Change? | Evidence... | |---|---|---| | Umm! A student removes a loaf of bread hot from the oven. The student cuts a slice off the loaf and spreads butter on it. | Physical | No change in substances. No unexpected color change, temperature change or gas given off. | | Your friend decides to toast a piece of bread, but leaves it in the toaster too long. The bread is black and the kitchen if full of smoke. | Chemical | Smoke and smells are formed, could not be reversed | | You forgot to dry the bread knife when you washed it and reddish brown spots appeared on it. | Chemical | Change could not be reversed | | You blow dry your wet hair. | Physical | Change in state | | In baking biscuits and other quick breads, the baking powder reacts to release carbon dioxide bubbles. The carbon dioxide bubbles cause the dough to rise. | Chemical | Bubble Formation | | You take out your best silver spoons and notice that they are very dull and have some black spots. | Chemical | Change cannot be reversed | | A straight piece of wire is coiled to form a spring. | Physical | Change in the shape of the wire but not identity | | Food color is dropped into water to give it color. | Physical | Change could be reversed | | Chewing food to break it down into smaller particles represents a Physical change, but the changing of starch into sugars by enzymes in the digestive system represents a Chemical change. | Physical | Chewing food presents changes of shape in smaller particles is physical, while starch changing into sugars is chemical as change cannot be reversed. | | In a fireworks show, the fireworks explode giving off heat and light. | Chemical | Explosions are formed. | ## Introduction to Ionic Bonding An ionic compound forms when one type of atom gives its outermost electrons to another type of atom and the two become attracted because of the positive and negative charges of the resulting ions, or charged atoms. ### 1. Draw the Lewis Structure for Mg & Cl Mg: [Mg] ^2+ Cl: [Cl] ^- ### Formula Unit: MgCl2 ### Name of Compound: Magnesium Chloride ### 2. Draw the Lewis Structure for Mg & S Mg: [Mg] ^2+ S: [S] ^2- ### Formula Unit: MgS ### Name of Compound: Magnesium sulfide ### 3. Draw the Lewis Structure for K & F K: [ K] ^+ F: [F]^- ### Formula Unit: KF ### Name of Compound: Potassium Flouride ### 4. Draw the Lewis Structure for K & O K: [ K] ^+ O: [O] ^2- ### Formula Unit: K₂O ### Name of Compound: Potassium Oxide ### 5. Draw the Lewis Structure for Be & N Be: [Be] ^2+ N: [N] ^3- ### Formula Unit: Be₃N₂ ### Name of Compound: Beryllium Nitride ### 6. Draw the Lewis Structure for Ca & P Ca: [Ca] ^2+ P: [P] ^3- ### Formula Unit: Ca₃P₂ ### Name of Compound: Calcium Phosphate ### 7. Draw the Lewis Structure for Al & F Al: [Al] ^3+ F: [F] ^- ### Formula Unit: Al F₃ ### Name of Compound: Aluminum Flouride ### 8. Draw the Lewis Structure for Ca & I Ca: [Ca] ^2+ I: [I] ^- ### Formula Unit: CaI₂ ### Name of Compound: Calcium Iodide ### 9. Draw the Lewis Structure for Rb & O Rb: [Rb] ^+ O: [O] ^2- ### Formula Unit: Rb₂O ### Name of Compound: Rubidium Oxide ### 10. Draw the Lewis Structure for Sr & F Sr: [Sr] ^2+ F: [F] ^- ### Formula Unit: SrF₂ ### Name of Compound: Strontium Flouride ### 11. Draw the Lewis Structure for Al & Cl Al: [Al] ^3+ Cl: [Cl] ^- ### Formula Unit: AlCl₃ ### Name of Compound: Aluminum Chloride ### 12. Draw the Lewis Structure for Mg & P Mg: [Mg] ^2+ P: [P] ^3- ### Formula Unit: Mg₃P₂ ### Name of Compound: Magnesium Phosphate ### 13. Draw the Lewis Structure for B & O B: [B] ^3+ O: [O] ^2- ### Formula Unit: B₂O₃ ### Name of Compound: Boron Oxide ### 14. Draw the Lewis Structure for Be & S Be: [Be] ^2+ S: [S] ^2- ### Formula Unit: BeS ### Name of Compound: Beryllium Sulfide ## Writing the Chemical Formula of Ionic Compounds Draw the Lewis structure showing the bond between aluminum & oxygen Al: [Al] ^3+ O: [O] ^2- => 2[Al] ^3+ 3[O] ^2- = Al2O3 Aluminum Oxide ### 1. Writing the formula for ionic compounds involving main group metals | Name of Cation | Name of Anion | Formula | |---|---|---| | Aluminum | Oxide | Al₂O₃ | | Lithium | Bromide | LiBr | | Magnesium | Flouride | MgF₂ | | Potassium | Oxide | K₂O | | Calcium | Sulfide | CaS | | Aluminum | Iodide | AlI₃ | | Barium | Bromide | BaBr₂ | | Aluminum | Sulfide | Al₂S₃ | | Calcium | Phosphide (P³) | Ca₃P₂ | | Lithium | Selenide | Li₂Se | ### 2. Writing the formula for ionic compounds involving transition metals. | Ion | Name | Example of Compound | |---|---|---| | Cu+ | copper(I) ion | copper(I) oxide, Cu₂O | | Cu²⁺ | copper(II) ion | copper(II) oxide, CuO | | Fe²⁺ | iron(II) ion | iron(II) chloride, FeCl₂ | | Fe³⁺ | iron(III) ion | iron(III) chloride, FeCl₃ | ### 3. Writing formula for ionic compounds with polyatomic ions | Name | Formula | Name | Formula | |---|---|---|---| | Ammonium | NH₄⁺ | Acetate | C₂ H ₃O₂⁻ | | Hydroxide | OH⁻ | Peroxide | O₂²⁻ | | Nitrate | NO₃⁻ | Permanganate | MnO₄⁻ | | Sulfate | SO₄²⁻ | Hydrogen sulfate | HSO₄⁻ | | Carbonate | CO₃²⁻ | Hydrogen carbonate | HCO₃⁻ | | Phosphate | PO₄³⁻ | Hydrogen phosphate | HPO₄²⁻ | | Chromate | CrO₄²⁻ | Dichromate | Cr₂O₇²⁻ | | Silicate | SiO₃²⁻ | Hypochlorite | OCl⁻ | | Cyanide | CN⁻ | ### Write the name of each of the following compounds. 1. NH₄Cl - Ammonium Chloride 2. HClO₂ - Hydrogen Chlorite 3. Ca(BrO₃)₂ - Calcium Bromate 4. BeSO₄ - Beryllium Sulfate 5. (NH₄)₃N - Ammonium nitride ### Write the chemical formula for each of the given names. 11. Na₂CrO₄ - Sodium chromate 12. Ba(NO₃)₂ - Barium nitrate 13. (NH₄)₂SO₄ - Ammonium sulfate 14. Al(OH)₃ - Aluminum hydroxide 15. Ca₃(PO₄)₂ - Calcium phosphate ## Properties of Ionic Compounds ### Observation 1 Place some salt on a slide and view it under a microscope at different magnifications. Draw your observations below, adding any detail you think necessary. ### Observation 2 Ensure your working area is clear. Tie long hair up and wear safety goggles. Using a Bunsen burner on a blue roaring flame, gently heat a small amount of salt in a test tube. What happens? The electrostatic forces between the positive sodium ions and negative chloride stoms are strong, ions arrange themselves into a repeating pattern and have lots of energy. ### Challenge One grain of salt contains, on average, over a trillion atoms of sodium and chlorine. Thinking back to last lesson on ionic bonding, can you predict the arrangement of the sodium and chlorine ions? Use your observations from step 1 to think about the overall shape, then think how the ions would be arranged within that shape. ### Observation 3 Place a small amount of salt in a beaker. Set up a circuit with a cell, bulb and wires. Incorporate the beaker with salt into the circuit. Does the bulb light up? No ### Why do you think this is? Ionic compounds conduct electricity when melted or dissolved in water. As a solid, ions are held fixed in position and the compound cannot conduct electricity. However, when the compound is dissolved in a solvent or molten, ions dissociate and are free to move and conduct electricity. ### Observation 4 Now add water to the beaker of salt and repeat. Does the bulb light up? Yes ### Why do you think this is? Ionic compounds are usually soluble in water. ## Introduction to Covalent Bonding Covalent bonding occurs when atoms share pairs of electrons instead of giving and receiving. The bond is included in the valence shell of banding atoms. Covalent bonding occurs between atoms of non-metals. | Compound | Element 1 (metal or non-metal?) | Element 2 (metal or non-metal?) | Bond Type | |---|---|---|---| | NO₂ | N= non-metal | O= non-metal | covalent | | NaCl | Na= metal | Cl= non-metal | ionic | | SO₂ | S= non-metal | O= non-metal | covalent | | PCl₃ | P= non-metal | Cl= non-metal | covalent | | MgBr₂ | Mg= metal | Br= non-metal | ionic | ### a. Draw a dot and cross diagram to show how hydrogen and chlorine would be bonded together. H:Cl: ### b. What type of bond is this? Covalent ### c. How do you know? Both are non-metals. ### d. What state of matter would you expect HCl to be at when at room temperature? Gas ### e. How do you know this? Oue to the weak intermolecular forces between the simple molecules of HCl, little energy is required to overcome these forces and change solid to liquid and a liquid to gas. They tend not to have melting/boiling points. ### f. Would this simple molecule be able to conduct electricity? No ### g. How do you know this? The simple molecules themselves do not have a charge, unlike ions, they have no free electrons to carry the charge. ## Drawing Lewis Structures to Represent Covalent Compounds ### Draw lewis dot structures for an atom of each of following elements: * 1. K - [K]^+ * 2. Si - [Si] * 3. Ar - [Ar] * 4. As - [As] ### For each of the following, write the formula, draw the Lewis dot structure, and draw the model, and determine the type of bond. | Chemical formula | Total Number of Valence Electrons | Lewis Dot Structure | |---|---|---| | CH₄ | 8 | [H][H][C][H][H] | | NH₃ | 8 | [H][N][H][H] | | CF₄ | 32 | [F][F][C][F][F] | | CO₂ | 16 | [O]=[C]=[O] | | BF₃ | 24 | [F][B][F][F] | | C₄H₆ | 24 | [H][C]=[C]-[C]=[C][H] | | H₂O | 8 | [H][O][H] | | Cl₂ | 14 | [Cl]-[Cl] | | PF₃ | 26 | [F][P][F][F] | | HF | 8 | [H]-[F] | | N₂ | 10 | [N]=[N] | | C₂H₄ | 12 | [H][C]=[C][H][H] | ## Naming and Properties of Covalent Compounds ### Write the formulas for the following covalent compounds: 1) Hexaboron monosilicide - B₆Si 2) Antimony tribromide - SbBr₃ 3) Chlorine dioxide - ClO₂ 4) Hydrogen monoiodide - HI 5) Iodine pentafluoride - IF₅ 6) Dinitrogen trioxide - N₂O₃ 7) Ammonia - NH₃ 8) Phosphorus triiodide - PI₃ ### Write the names for the following covalent compounds: 9) P₄S₅ - Tetraphosphorus Pentasulfide 10) O₂ - Dioxygen 11) SeF₆ - Selenium Hexaflouride 12) Si₂Br₆ - Disilicon hexabromide 13) SCl₄ - Sulfur tetrachloride 14) CH₄ - Carbon tetrahydride (methane) 15) B₂Si - Diboron monosilicide 16) NF₃ - Nitrogen triflouride Non-metals react together to form compounds which are held together by covalent bonds. These bonds hold the atoms together very close. If these substances are made of simple molecules, they have low melting points and boiling points. So at room temperature they often exist as gasses and liquids or as solids which melt easily. This is because only a small amount of energy is needed to break the weak forces of attraction between these molecules. Simple covalent molecules do not conduct electricity because there are no free ions/electrons and no overall charge on molecules. ## Covalent Network Solids ### Starter Activity A compound melts at 20°C. What kind of structure do you think it has? Why do you think so? Will it conduct electricity at 25°C? Give a reason. ### Covalent Network Solids You will be given a picture of a substance. Based on the structure and form of the substance, predict the properties it will have. ## Practice Problem The structures of diamond and chlorine are shown below. ### (a) Describe the structure of these two substances. Use the list of words to help you. - covalent - diatomic - giant - macromolecule - molecule - structure Diamond: giant covalent macromolecule, each carbon is bonded covalently to other carbons to form a huge lattice structure. Chlorine: simple molecular substance, diatomic molecule held by strong covalent bonds. ### Potassium chloride is an ionic substance but iodine is a molecular substance. How do most ionic and molecular substances differ in their - **solubility in water?** Ionic - always soluble. Covalent - not soluble except polar. - **electrical conductivity?** Ionic compounds conduct electricity only molten or in solution. Covalent - don't conduct electricity ## Metallic Bonding Metals are giant structures of metal ions in a regular lattice structure and in tightly packed layers. Metals have a regular arrangement of positive ions surrounded by a sea of electrons. Electrons have been lost from the metal atoms and are delocalized. This means that they can move freely through the atomic structure of the metal. As a result of free electrons, the metal atoms become attracted to the sea of electrons. The particles in a metal are thus held together by strong electrostatic and a lot of energy is needed to separate the particles. ### Properties of Metallic Compounds | Property | Explanation | |---|---| | Most Metals have high melting/boiling points. | The electrostatic forces of attraction between metal cations and delocalized electrons is strong and therefore more heat energy is needed to overcome when melting/boiling. | | Metals are malleable and ductile. | Ductile means they can be drawn out into layers. Malleable means they can be bent and pressed into sheets. This is because the layers can slide over each other, the delocalized electrons are free to move too. The layers can slide without breaking the metallic bonds, because the delocalized electrons are free to move too. | | Metals are good conductors of heat and electricity. | Heat: That is because the delocalized electrons take in heat energy which makes them move faster (with more kinetic energy). They quickly transfer the heat through the metal structure. Electricity: The free delocalized electrons carrying charge, when a voltage is applied across the metal. | ## The diagrams below show the structure of an alloy and pure iron. Use the diagrams to explain why the alloy is harder than the pure iron. In alloys, the addition of atoms of another element (metals or non-metals) disrupts the regularly arranged layers. The different sized atoms make it more difficult for layers to slide over one another, making alloys harder and stronger than pure metals. ## Types of Chemical Reactions ## Watch: https://www.youtube.com/watch?v=TX6BYceUSLO And fill in the information in the table below: | Type of Reaction | Definition | Generalized reaction | |---|---|---| | Synthesis | Two or more substances combine to make a single product. | A + B = AB | | Decomposition | One substance breaks down to form two or more simpler substances | AB -> A + B | | Single Replacement | When one element replaces another element in a compound | A + BC = AC + B | | Double Replacement | The positive ion of one compound replaces the + ion of another compound, two new compounds are formed. | AB + CD - AD+ CB | | Combustion | When a substance burns with oxygen to give produce heat and light | CH4 + O2 -> CO2 + H2O | ## Types of Chemical Reactions-Demonstration Ionic Substances can be broken down by passing electricity through them. This process is called electrolysis. | # | Type of reaction | Chemical Reaction | |---|---|---| | 1 | Combination or Synthesis Reaction | | | 2 | Decomposition Reaction | | | 3 | Single-replacement Reaction | | | 4 | Double-replacement Reaction | | | 5 | Combustion Reaction | | ## Types of Chemical Reactions-Clue Game Six contestants on a reality TV show were stunned to find their lowest scoring colleague was "injured." They must figure out the crime before the bell rings. The question is Whodunnit? And how... The Player, Last Known Whereabouts and Method that are left unaccounted for -- is the solution. | The Players | The Last Known Whereabouts | The Method | |---|---|---| | Professor Astro | | Chemical Poisoning | | Mrs. Bio | Gym | Cougar Attack | | Mr. Chem | Kitchen | Electrocution | | Dr. Earth | Library | Fallen Object | | Coach Physics | Movie Theater | Stubbed Toe | | Miss Zoo | Pool | Venomous Bite | ## Balancing Chemical Reactions ### Access the gizmo: Balancing Chemical Equations Prior Knowledge Questions (Do these BEFORE using the Gizmo.) The scouts are making s'mores out of toasted marshmallows, chocolate, and graham crackers. 1. What is wrong with the image below? *Not enough Carbon* 2. Assuming a s'more requires two graham crackers, one marshmallow, and one piece of chocolate, how many s'mores could you make with the ingredients shown? *7* ### Gizmo Warm-up In a chemical reaction, reactants interact to form products. This process is summarized by a chemical equation. In the Balancing Chemical Equations Gizmo, look at the floating molecules below the initial reaction: H2 + O2 → H2O. 1. How many atoms are in a hydrogen molecule (H₂)? *2* 2. How many atoms are in an oxygen molecule (O2)? *2* 3. How many hydrogen and oxygen atoms are in a water molecule (H₂O)? *3* 4. In general, what does a subscript (such as the "2" in H₂) tell you about the molecule? *Two of such atoms is in each molecule* 5. A chemical equation is balanced if the number of each type of atom on the left side is equal to the number of each type on the right side. Is this reaction balanced? *No* ### Activity A: Balancing equations Get the Gizmo ready: * Check that the Synthesis reaction is selected and that all coefficients are set to one. (The coefficients are the numbers in the boxes.) Introduction: The equation H2 + O2 → H2O is unbalanced because there are two oxygen atoms on the reactants side of the equation, and only one on the products side of the equation. To balance the equation, you cannot change the structure of any of the molecules, but you can change the number of molecules that are used. Question: How are chemical equations balanced? ### 1. Balance: Turn on Show histograms. The equation is balanced when there are equal numbers of each type of atom represented on each side of the equation. In the Gizmo, use the up and down arrows to adjust the numbers of hydrogen, oxygen, and water molecules until the equation is balanced. When you are done, turn on Show summary to check your answer. Write the balanced equation here: 2 H2 + 1 O2 → 2 H2O ### 2. Solve: Turn off Show summary. Use the Choose reaction drop down menu to see other equations, and balance them. Check your answers and then write the balanced equations. - 2 Al + 6 HCl → 2 AlCl3 + 3 H₂ - 2 NaCl + 2 Na+ Cl₂ - Na2S + 2 HCI → 2 NaCl + H2S - CH4 + 2 O₂ → CO₂ + 2 H2O ### 3. Practice: Balance the following chemical equations. (These equations are not in the Gizmo.) A, 2 Na + 1 Cl2 → 2 NaCl B. 2 Na + 2 H2O → 2 NaOH + H₂ C. 2 Mg + 1 O2 → 2 MgO D. 2 KClO₃→ 2 KCl + 3 O₂ E. 2 Al + 3 CuO → Al₂O₃ + 3 Cu F. 2 I + Na2S2O3 → 2 NaI + Na₂S₄O₆ G. 3 Mg + 1 P4 → Mg₃P₂ ### Activity B: Classifying reactions Get the Gizmo ready: * Turn off Show summary and Show histograms. Introduction: Chemical equations show how compounds and elements react with one another. An element is a substance consisting of one kind of atom, such as aluminum (Al) or oxygen gas (O2). A compound is a substance made of more than one kind of atom, such as water (H₂O) or table salt (NaCl). Question: How are chemical reactions classified? 1. Match: Most chemical reactions can be classified as one of four types. Using the chemical equations in the Gizmo as a guide, match the following definitions to the type of reaction. - One reactant is broken down into two or more products. - **Decomposition** - A fuel is combined with oxygen to produce carbon dioxide and water. - **Combustion** - Two or more reactants combine to form one product. - **Synthesis** - Two compounds react to form two different compounds. - **Double Replacement** - A compound reacts with an element to form a new compound and a different element. - **Single replacement** ### 1. Practice: Balance each of the chemical equations below. (Some equations may already be in balance.) In the space to the right, classify the reaction as a synthesis, decomposition, single replacement, or double replacement reaction. A. AgNO3 + KCI → AgCl + KNO3 - Double displacement B. 2 H2O + SO3 → H2SO4 - Synthesis C. 2 KI+ Cl2 → 2KCl + I2 - Double displacement D. NaHCO3 → Na2 CO3 + H2O + CO2 - Decomposition E. Zn + 2 HCI → ZnCl2 + H₂ - Single Replacement F. BaCl2 + Na2SO4 → BaSO4 + 2NaCl - Double displacement G. C3H8 + 5 O2 -> 3 CO2 + 4 H2O - Combustion H. 2 Al + 3 CuCl2→2 AlCl3 + 3 Cu - Double displacement ## Homework: Complete and balance the following chemical equations: 1. Iron combines with oxygen to form rust, which is also known as iron(II) oxide. Fe + 3 O2 → 2 Fe2O3 2. A solution of hydrogen chloride reacts with sodium carbonate to produce carbon dioxide, sodium chloride, and water. 2HCl + Na2CO3 → CO2 + 2NaCl + H2O 3. When aluminum metal is exposed to oxygen, a metal oxide is formed 4Al + 3O2 → 2Al2O3 4. Chromium (III) sulphate reacts with potassium carbonate Cr2(SO4)3 + 3K2CO3 → Cr2(CO3)3 + 3K2SO4 ## Solubility Rules Salts are compounds that are formed through the reactions of metals and non-metals (all ionic compounds can be referred to as salts except those where the non-metal atom is only oxygen or hydrogen) Some salts are soluble in water and others are partially soluble or insoluble. A reaction which produces an insoluble salt is called a precipitation reaction and the salt produced is the precipitate. In the chemical equation, the precipitate is shown as being a solid, with the state symbol (s) ### Label each picture below with one of the following labels (one is used more than once) A - Pure water B - After a soluble salt is added to water C - After an insoluble salt is added to water D - After two soluble salts are mixed and all combinations of the ions are soluble (no chemical change) E - After two soluble salts are mixed and a precipitate has formed ### Activity: A Systematic Approach | | HCl / Calcium Hydroxide | Silver Sulfate / Calcium Hydroxide | Potassium Nitrate / Calcium Hydroxide | Hydrobromic Acid / Calcium Hydroxide | Sodium Carbonate / Calcium Hydroxide | |---|---|---|---|---|---| | **Magnesium Chromate** | | | | | | | **Lead Nitrate** | | | PbI₂ | | | | **Mercury(II) Sulfate** | | | | | | | **Barium Chloride** | | | | | | ## Formulate the balanced chemical equations for the reactions in the lab: - Ca(OH)2 + 2HCl ------> CaCl2 + 2H2O - Ca(OH)2 + CuSO4 ------> CaSO4 + Cu(OH)2 - Ca(OH)2 + Na2CO3 ------> CaCO3 + 2NaOH - Pb(NO3)2 + 2HCl ------> PbCl2 + 2HNO3 - Pb(NO3)2 + CuSO4 ------> PbSO4 + Cu(NO3)2 - Pb(NO3)2 + 2KI ------> PbI2 + 2KNO3 - Pb(NO3)2 + Na2CO3 ------> PbCO3 + 2NaNO3 - 2AgNO3 + CuSO4 ------> Ag2SO4 + Cu(NO3)2 - AgNO3 + KI ------> AgI + KNO3 - 2AgNO3 + Na2CO3 ------> Ag2CO3 + 2NaNO3 ## Molecular Equations and Ionic Equations ### Starter Activity Formulate the chemical equations for the following word equations: a) When fluorine gas is put into contact with calcium metals at high temperatures, calcium fluorine powder is created. F2 + Ca -> CaF2 b) When sodium metal reacts with iron (II) chloride, iron metal and sodium chloride is formed. 2 Na + FeCl2 -> 2NaCl + Fe c) When dissolved beryllium chloride reacts with dissolved silver nitrate in water, beryllium nitrate and silver chloride is formed. BeCl2 + 2AgNO3 -> Be(NO3)2 + 2AgCl ### Steps to writing net ionic equations 1. Write the Reaction 2. Balance the Equation 3. Identify "Insolubles" 4. Understand the Visual 5. Split Up All Compounds 6. Understand the Visual 7. Write Net lonic - Write out the reactants and products that would form. - Balance the equation written in the last step. - Bold, circle, underline, or highlight the insoluble compound. - Draw out the balanced equation with molecules. - Split up all compounds that are soluble in water. - Draw out the equation again now that everything is split up. Make sure to draw everything as "broken up" if the compounds are soluble. - Cancel everything that is soluble, or "split up", from left to right so that it is obvious which two things are combining to become the one solid compound that doesn't dissolve. ### Example **Write the Reaction** NaCl + Pb(NO3)2 -> NaNO3 + PbCl2 **Balance the Equation** NaCl + Pb(NO3)2 -> NaNO3 + PbCl2 **Identify "Insolubles"** NaCl(aq) + Pb(NO3)2(aq) -> NaNO3(aq) + PbCl2(s) **Understand the Visual** [Na]^+ + [Cl]^- + [Pb] ^2+ + 2[NO3]^- -> [Na]^+ + 2[NO3]^- + [PbCl2] [Na]^+ + [Cl]^- + [Pb] ^2+ + 2[NO3]^- -> [Na]^+ + [NO3]^- + [Pb] ^2+ + [Cl]^- + [PbCl2] **Split Up All Compounds** - 2 Na(aq) + 2Cl (aq) + Pb(aq) + 2NO3(aq) → 2 Na(aq) + 2NO3(aq) + PbCl2(s) **Understand the Visual** - 2 Na(aq) + 2Cl (aq) + Pb(aq) + 2NO3(aq) → 2 Na(aq) + 2NO3(aq) + PbCl2(s) **Write Net Ionic** - 2Cl(aq) + Pb(aq) → PbCl2(s) ### Practice Questions: Formulating Equations 1. Sodium chloride and lead II nitrate **Molecular Equation** 2NaCl(aq) + Pb(NO3)2(aq) → 2NaNO3(aq) + PbCl2(s) **Complete Ionic Equation** 2Na(aq) + 2Cl(aq) + Pb(aq) + 2NO3(aq) → 2Na(aq) + 2NO3(aq) + PbCl2(s) **Net Ionic Equation** 2Cl(aq) + Pb(aq) → PbCl2(s) 2. Sodium carbonate and Iron II chloride **Molecular Equation** Na2CO3(aq) + FeCl2(aq) → 2NaCl(aq) + FeCO3(s) **Complete Ionic Equation** 2Na(aq) + CO3(aq) + Fe(aq) + 2Cl(aq) → 2Na(aq) + 2Cl(aq) + FeCO3(s) **Net Ionic Equation** Fe(aq) + CO3(aq) → FeCO3(s) 3. Magnesium hydroxide and hydrochloric acid **Molecular Equation** Mg(OH)2(aq) + 2HCl(aq) → MgCl2(aq) + 2H2O(l) **Complete Ionic Equation** - Mg(aq) + 2OH(aq) + 2H(aq) + 2Cl(aq) -> Mg(aq) + 2Cl(aq) + 2H₂O(l) **Net Ionic Equation** - 2OH(aq) + 2H(aq) -> 2H₂O(l) 4. Ammonium phosphate and zinc nitrate **Molecular Equation** (NH4)3PO4(aq) + 3Zn(NO3)2(aq) → 3NH4NO3(aq) + Zn3(PO4)2(s) **Complete Ionic Equation** - 3NH4(aq) + PO4(aq) + 3Zn(aq) + 6NO3(aq) → 3NH4(aq) + 6NO3(aq) + Zn3(PO4)2(s) **Net Ionic Equation** - 3Zn(aq) + 2PO4(aq) → Zn3(PO4)2(s) 5. Lithium hydroxide and barium chloride **Molecular Equation** 2LiOH(aq) + BaCl2(aq) → 2LiCl(aq) + Ba(OH)2(s) **Complete Ionic Equation** - 2Li(aq) + 2OH(aq) + Ba(aq) + 2Cl(aq) → 2Li(aq) + 2Cl(aq) + Ba(OH)2(s) **Net Ionic Equation** - Ba(aq) + 2OH(aq) → Ba(OH)2(s) 6. Sodium carbonate and hydrochloric acid produces sodium chloride, carbon dioxide and water **Molecular Equation** Na2CO3(aq) + 2HCl(aq) → 2NaCl(aq) + CO2(g) + H2O(l) **Complete Ionic Equation** - 2Na(aq) + CO3(aq) + 2H(aq) + 2Cl(aq) → 2Na(aq) + 2Cl(aq) + CO2(g) + H₂O(l) **Net Ionic Equation** - H(aq) + CO3(aq) → H2O(l) + CO2(g) 7. Iron III chloride and magnesium metal **Molecular Equation** 2FeCl3(aq) + 3Mg(s) → 3MgCl2(aq) + 2Fe(s) **Complete Ionic Equation** 2Fe(aq) + 6Cl(aq) + 3Mg(s) → 3Mg(aq) + 6Cl(aq) + 2Fe(s) **Net Ionic Equation** 2Fe(aq) + 3Mg(s) -> 2Fe(s) + 3Mg(aq) 8. Barium Bromide and sodium sulfate **Molecular Equation** BaBr2(aq) + Na2SO4(aq) → BaSO4(s) + 2NaBr(aq) **Complete Ionic Equation** Ba(aq) + 2Br(aq) + 2Na(aq) + SO4(aq) → BaSO4(s) + 2Na(aq) + 2Br(aq) **Net Ionic Equation** Ba(aq) + SO4(aq) → BaSO4(s)