SNC2D Exam Review Jan 2024 Chemistry PDF

SNC2D1 EXAM REVIEW Unit 1: CHEMISTRY – Chemical Reactions 1. Name the chemical families what are the ionic charges for each group? Groups are found in the vertical columns! Alkali metals Group I or 1 1+ (soft, highly reactive metals) Alkaline Earth Metals...

SNC2D1 EXAM REVIEW Unit 1: CHEMISTRY – Chemical Reactions 1. Name the chemical families what are the ionic charges for each group? Groups are found in the vertical columns! Alkali metals Group I or 1 1+ (soft, highly reactive metals) Alkaline Earth Metals Group II or 2 2+ (light, reactive metals) Halogens Group VII or 17 1- (of the most reactive groups) Noble or Inert Gases Group VIII or 18 0 (stable and rarely react) 2. Draw Bohr – Rutherford diagrams of beryllium, lithium, oxygen, nitrogen, fluoride. 3. Draw Bohr – Rutherford diagrams showing the electron movement that occurs when magnesium and nitrogen react to form a compound. (a) Determine the ionic charges when magnesium and nitrogen atoms form ions. Mg 2+ N3- (b) Give the chemical formula and the chemical name of the compound formed. Mg3N2 → Magnesium nitride 4. Compare the formation of ionic bonds and covalent bonds. Ionic Bonding Ionic compounds are made up of one or more positive metal ions (cations) and one or more negative nonmetal ions (anions). Form when electrons are transferred from a metal to a positive ion (cations) and a negative ion (anions). The oppositely charged ions are held together by an ionic bond. Ionic bond: a strong bond that results from the strong attraction of positive and negative ions in an ionic compound. Due to the strength of the attractive forces of the ionic bond, ionic compounds are hard, brittle, solids at room temperature with high melting points. Most ionic compounds are electrolytes, which means they dissolve in water to produce solutions that conduct electricity. Examples: Sodium chloride – NaCl, Copper (II) sulfate – CuSO4 Covalent Bonding Molecular compounds are formed from two or more nonmetal atoms. Form when two non-metals share outer electrons. This bond is known as a covalent bond. Covalent bond: a weak bond that results from the sharing of outer electrons between non-metal atoms. Examples: Carbon monoxide (CO), Carbon dioxide (CO2) and seven diatomic molecules such as H2(g) 5. Write the formula for the following compounds: (a) Aluminum nitride – AlN (e) Lead (II) iodide PbI2 (i) Copper(I) nitride Cu3N (b) Sodium fluoride – NaF (f) Iron (II) bromide FeBr2 (c) Potassium bromide – KBr (g) Dinitrogen trioxide N2O3 (d) Calcium phosphate Ca3(PO4)2 (h) Nitrogen tribromide NBr3 6. Write the name for the following compounds: (a) CO2 Carbon dioxide – molecular (f) AlBr3 Aluminum bromide – ionic (b) CF4 Carbon tetrafluoride – molecular (g) Fe2O3 Iron (III) oxide – ionic (c) HCl Hydrochloric acid – special (oxyacid) (h) Sn3P2 Tin (II) phosphide – ionic (d) NH3 Ammonia – molecular (i) Cu(OH)2 Copper (II) hydroxide – ionic (e) K2SO4 Potassium sulfate – ionic 7. Explain and provide an example for each of the following types of reactions: synthesis, decomposition, single displacement, double displacement. Synthesis A + B → AB Two reactants combine to form one Word equation: Sodium + Chlorine (gas) → Sodium chloride complex product. Skeleton equation: Na + Cl2 → NaCl Balanced equation: 2Na + Cl2 → 2NaCl Decomposition AB → A + B One complex reactant is broken Word equation: Sodium chloride → Sodium + Chlorine (gas) down into two or more simper Skeleton equation: NaCl → Na + Cl2 products. Balanced equation: 2NaCl → 2Na + Cl2 Single Displacement A reaction in which an element displaces another element in a compound, producing a new compound and new element. Rule: “Like Replaces Like” (e.g., Metal  Metal) A + BC → AC + B Word equation: Aluminum + Silver nitrate → Aluminum nitrate + Silver Skeleton equation: Al + AgNO3 → Al(NO3)3 + Ag Balanced equation: 3Al + 3AgNO3 → Al(NO3)3 + 3Ag Double Displacement A reaction that occurs when elements in different compounds displace each other or exchange places, producing two new compounds. AB + CD → AD + CB Word equation: Lead(II) nitrate + Potassium iodide → Lead(II) iodide + Potassium nitrate Skeleton equation: Pb(NO3)2 + KI → PbI2 + KNO3 Balanced equation: Pb(NO3)2 + 2KI → PbI2 + 2KNO3 8. Compare and contrast complete hydrocarbon combustion versus incomplete hydrocarbon combustion reactions. Complete Hydrocarbon Combustion (Safe) If enough oxygen is available, hydrocarbons burn completely and safely. Only products released are carbon dioxide and water. Hydrocarbon + Oxygen (gas) → Carbon dioxide + Water + energy CXHY + O2(g) → CO2 + H2O + energy Incomplete Hydrocarbon Combustion (Dangerous) When the oxygen supply is limited, hydrocarbons undergo incomplete combustion which produce four products: Carbon dioxide, water, carbon monoxide and carbon. CXHY + O2(g) → CO2 + H2O + CO + C + energy Though carbon dioxide and water are safe, the carbon monoxide and carbon are highly toxic and could be deadly. Therefore, it is critical that hydrocarbon combustion reactions are always performed in a well-ventilated area. 9. Label the products and the reactants in the following word equation: C3H8 + O2(g) → CO2 + H2O + energy (a) Write the balanced equation for this reaction. C3H8 + 5O2(g) → 3CO2 + 4H2O + energy (b) What type of chemical reaction is this? Complete Hydrocarbon Combustion (2 products) (c) What precautions should be taken when performing this reaction? Why? Poor oxygen supply could lead to an incomplete combustion reaction which produces four products. Though carbon dioxide and water are safe, the carbon monoxide and carbon are highly toxic and could be deadly. Therefore, it is critical that hydrocarbon combustion reactions are always performed in a well-ventilated area. 10. Describe a neutralization reaction. Provide two examples of neutralization reactions. Acids and bases react together in neutralization reactions. An acid and a base react to form → Water + Ionic compound (a type of salt)  The products have a pH closer to 7 (neutral) than either of the reactants. Acids form hydrogen ions (H+) in water. Bases release hydroxide ions (OH-) in water. Hydrogen ions and Hydroxide ions react to produce H2O water! Neutralization reactions are double displacement reactions: AB + CD → AD + CB Example: HCl + NaOH → H2O + NaCl 11. When 2.5 g of zinc metal is placed in 52.9 g of hydrochloric acid, the final solution of zinc chloride weighs 54.8 grams. (a) What is the mass of the missing product? Show your calculation. 2.5 g + 52.9 g = 55.4 g Reactant Mass 55.4 g – 54.8 g = 0.6 g Product Mass (b) Write a chemical equation for this reaction. Zn + 2HCl → ZnCl2 + H2(g) (c) What happened to the missing mass? Does the law of conservation still apply in this situation? The law of conservation of mass applies to all reactions, as such the missing mass can be accounted for in the 0.6 g of hydrogen (gas) that escaped the reaction vessel (apparatus). 12. Balance the following equations and classify the type of reaction where indicated: (a) 2K2O → 4K + O2(g) (d) P4 + 6N2O → P4O6 + 6N2 (b) Cu(NO3)2 + 2NaOH → Cu(OH)2 + 2NaNO3 (e) 2H2(g) + O2(g) → 2H2O (c) CH4 + O2(g) → CO2 + H2O + CO + C + energy (f) 3Fe + Al2(SO4)3 → 3FeSO4 + 2Al Incomplete hydrocarbon combustion cannot be balanced! 13. Compare acids and bases using a graphic organizer. Acids Bases ▪ Corrosive ▪ Corrosive ▪ Water soluble ▪ Water soluble ▪ Sour taste* ▪ Bitter taste* ▪ Non-slippery texture* ▪ Slippery texture* ▪ Neutralize bases ▪ Neutralize acids ▪ Turn blue litmus paper red ▪ Turn red litmus paper blue ▪ Molecular compounds: collide with water ▪ Ionic compounds molecules and break apart into ions! ▪ Electrolytes → electrical conductivity Separate ▪ Electrolytes → electrical conductivity Collide with into ions in water water molecules form ions HCl NaOH releases Na+ and OH- ions in water releases H+ and Cl- ions in water HNO3 Ba(OH)2 releases Ba2+ and OH- ions releases H+ and NO3- ions in water ▪ Referred to as “alkaline” ▪ React with metals to produce H2(g) ▪ Formulas include OH or CO3 ions. HCl(aq) + Zn → H2(g) + ZnCl2 NaOH – Sodium hydroxide ▪ React with carbonates to produce CO2(g) Ca(OH)2 – Calcium hydroxide ▪ HCl(aq) + NaHCO3 → CO2 + H2O + NaCl ▪ Formulas begin with H ▪ State symbol usually aqueous (aq) ▪ Binary acids contain only 2 elements: HCl(aq) – hydrochloric acid ▪ Oxyacids contain polyatomic ions: HNO3(aq) – nitric acid H2SO4(aq) – sulfuric acid 14. What is a chemical indicator? What colours would blue litmus paper, red litmus paper, phenolphthalein, and bromothymol blue turn when placed in an acid verse a base? Chemical (Acid-Base) indicators are substances which change colour depending on whether it is placed in an acid or base. Also refer to as pH Indicators Only a small amount of indicator compound is needed to produce a visible color change. Some indicators change from one color to another (bromothymol blue), while others change between colored and colorless (phenolphthalein). Indicators Colour in Acid Colour in Base Colour in Neutral Bromothymol blue Yellow Remains Blue Green Phenolphthalein Colourless Pink Colourless Blue Litmus Red Remains Blue Remains Blue Red Litmus Remains Red Blue Remains Red Universal pH Paper Universal pH Paper can give the pH value of the solution, whereas litmus paper can determine whether a solution is acidic or basic. Variety of color changes used to identify rough pH values. Roughly indicates the concentration of acids and bases, that is, how weak or strong the solution. The pH Scale is a numerical scale ranging from 0 to 14 that is used to compare the acidity of solutions. A chemicals pH value is a measure of how acidic or basic a solution is. There pH refers to the “power of Hydrogen” --- notice the “p” is lowercase! Acids have a greater concentration of hydrogen ions, while bases have less. Acid pH value 0 to 6 pH 0 strong acid → pH 6 weak acid Neutral pH value 7 Basic pH value 8 to 14 pH 8 weak base → 14 strong base