11G EoT1 2025 Updated Chemistry PDF

# EoT1 11Gen 2025 Chemistry Khakifa Bin Zayed School ## Mr. Osama Almustafa *** ### 1. Write the formula of a compound composed of atoms of elements **Text book + table 1** *** A compound formed when elements combine often has properties aren't anything like those of the individual elements. For e...

# EoT1 11Gen 2025 Chemistry Khakifa Bin Zayed School ## Mr. Osama Almustafa *** ### 1. Write the formula of a compound composed of atoms of elements **Text book + table 1** *** A compound formed when elements combine often has properties aren't anything like those of the individual elements. For example, potassium iodide is a compound made from the elements potassium and iodine. Potassium is a shiny, soft, silvery metal that reacts violently with water. Iodine is a blue-black solid that turns to a purple gas at room temperature. The chemical formula shows what elements a compound contains and the exact number of the atoms of each element in a unit of that compound. *** ### Table 1 Some Familiar Compounds | Common Name | Chemical Name | Chemical Formula | |---|---|---| | Sand | silicon dioxide | SiO₂ | | Milk of magnesia | magnesium hydroxide | Mg(OH)₂ | | Cane sugar | sucrose | C₁₂H₂₂O₁₁ | | Lime | calcium oxide | CaO | | Vinegar | acetic acid | CH₃COOH | | Laughing gas | dinitrogen monoxide | N₂O | | Grain alcohol | ethanol | C₂H₅OH | | Battery acid | sulfuric acid | H₂SO₄ | | Stomach acid | hydrochloric acid | HCl | *** Aspirin is a well-known medicine. It is used to treat fever, inflammation, pain and avoid major cardiovascular problems. An aspirin molecule is made of 9 carbon atoms, 8 hydrogen atoms and 4 oxygen atoms. What is the correct chemical formula for aspirin? - 9C₈H₄₀ - **C₉H₈O₄** - CHO - C₄H₄O₂ *** ## 2. Describe how the atom reaches the octet stability state **Text book + figures 3&4** *** The unique noble gases. An atom is chemically stable when its outer energy level is complete. The outer energy levels of helium and hydrogen are stable with two electrons. The outer energy levels of nearly all other elements are stable with eight. The noble gases are stable because they have a full outer energy level. **What is the reason behind the stability of the noble gases?** - **Noble gases have full outer energy levels.** - Noble gases have 2 valence electrons. - Noble gases lose their valence electrons to other elements. - Noble gases share electrons with other elements. *** Sulfur has 6 valence electrons. How it can become stable (obeys octet rule)? - A. By losing 6 electrons - **B. By gaining 2 electrons** - C. By losing 2 protons - D. By gaining 8 electrons *** ## 3. Explain how a positive ion and a negative ion are formed in an ionic compound **Text book + figure 5** *** Sodium (Na) and chlorine (Cl). When they combine, sodium loses one electron and chlorine gains one electron. From the electron dot diagram, chlorine now has a stable outer energy level, similar to a noble gas. **Using the following figure, Which statement is CORRECT?** - A. Na loses 1 electron and becomes negative ion - **B. Na loses 1 electron and becomes positive ion** - C. Cl loses 1 electron and becomes negative ion - D. Cl gains 1 electron and becomes positive ion **Which atom will gain 2 electrons to become stable?** - F Group 17 - **O Group 16** - Ne Group 18 - Ca Group 2 *** ## 4. Distinguish between cations and anions **Text book** *** An ion is a charged particle that has either more or fewer electrons than protons. **Cation** When an atom loses electrons and becomes a positively charged ion. **Anion** is when an atom gains electrons and becomes a negatively charged ion. *** **Which of the following statements is correct?** - **A. When an atom loses electrons, it becomes a positively charged ion and called Cation** - B. When an atom gains electrons, it becomes a positively charged ion and called Cation - C. When an atom loses electrons and becomes a negatively charged ion and called anion - D. When an atom loses electrons and becomes a negatively charged ion and called anion *** ## 5. Explain the process of electron transfer between atoms to form an ionic bond **Text book + figures 8&9** *** Potassium must transfer one electron to iodine in order for both to achieve stable outer energy levels. Compare and contrast the outer energy level of each atom before and after the transfer of the electron. **Select the electron-dot structure to complete the following reaction:** **Li• + • F:** - [Li⁻] + [:F:] **Which statements are true about the reaction between magnesium and chlorine atoms?** **Select 2 choice(s)** - **Mg and Cl atoms react and form MgCl₂.** - Each Mg atom needs 1Cl atom to be stable. - Mg atom loses 2 e to be stable and becomes Mg²⁺. - Cl gains 2 e and becomes Cl²⁻. - After losing 2 e, Mg doesn't have valence electrons. ## 6. Explain how atoms share electrons to form single or multiple covalent bonds **Text book + figures 10&11** *** Hydrogen and oxygen each contribute one electron to the hydrogen-oxygen bonds in a water molecule. **How double covalent bond forms?** - 0. + 0. → 0:0: - **B. Sharing 2 pairs of electrons** - A. Sharing 1 pair of electrons - C. Sharing 3 pairs of electrons - D. Sharing 4 pairs of electrons A carbon atom shares **four pairs** of electrons with each oxygen atom to form **two double** covalent bonds. *** ## 7. Explains the polarity and molecular geometry of some compounds **Text book + figures 14&15** *** A polar molecule is one in which the unequal sharing of electrons results in a slightly positive end and a slightly negative end. Non-polar molecule is a molecule that does not have oppositely charged ends. **Which statement is correct about the water molecule?** - The atoms in a water molecule are symmetrically shaped. - **The water molecule is nonpolar.** - The electrons are equally distributed between the three atom. - The oxygen atom has a greater nuclear charge than the hydrogen atom. **Choose the option that applies to the carbon tetrachloride molecule.** - **The symmetrical arrangement of atoms cancels out the dipole.** - Each chlorine atom carries a partial positive charge. - The four CCl bonds are polar. - The symmetrical arrangement of atoms adds up the dipole. **Consider the chlorine molecule (Cl₂) and select the type of bond that joins chlorine atoms.** - metallic bond - **nonpolar covalent bond** - polar covalent bond - ionic bond *** ## 8. Write the chemical formula for a binary ionic compound **Text book+ example Problem 1,2 + practice problems** **DETERMINE A CHEMICAL FORMULA** What is the formula for lithium nitride? **PRACTICE Problems** - What is the formula for potassium sulfide? - What is the formula for calcium chloride? - What is the formula for lead(IV) phosphide? **What is the chemical formula for the compound formed between magnesium (Mg²⁺) and cyanide ions (CN⁻)?** - MgCN₂ - Mg₂(CN) - Mg₂(CN)₂ - **Mg(CN)₂** **What is the formula for calcium oxide if the calcium ion has a charge of 2+ and the oxide ion has a charge of 2-?** - 2CaO - CaO₄ - **CaO** - Ca₂O **NAME A BINARY IONIC COMPOUND** What would a chemist name the compound CuCl? **PRACTICE Problems** - What is the name of AlCl₃? - What is the name of Li₂S? - What is the name of Cr₂O₃? *** ## 9. Write the chemical formula for compound with complex ions **Text book + tables 4 and 5** *** ### Table 4 Polyatomic Ions | Charge | Name | Formula | |---|---|---| | 1+ | ammonium | NH⁺₄ | | | acetate | C₂H₃O₂⁻ | | | chlorate | ClO₃⁻ | | | hydroxide | OH⁻ | | | nitrate | NO₃⁻ | | 2- | carbonate | CO₃²⁻ | | | sulfate | SO₄²⁻ | | 3- | phosphate | PO₄³⁻ | *** **write the chemical formula for ammonium phosphate.** **What is the chemical formula of the ionic compound that forms when NO₃⁻ and Ca²⁺ combined?** - Ca(NO₃)₂ - NO₃Ca - CaNO₃ - (Ca)₂NO₃ *** ## 10. Naming binary covalent compound **Text book + table 6** *** ### Table 6 Prefixes for Covalent Compounds | Number of Atoms | Prefix | Example | |---|---|---| | 1 | mono- | carbon monoxide | | 2 | di- | sulfur dioxide | | 3 | tri- | phosphorus trichloride | | 4 | tetra- | carbon tetrachloride | | 5 | penta- | dinitrogen pentoxide | | 6 | hexa- | uranium hexafluoride | | 7 | hepta- | dichlorine heptoxide | | 8 | octa- | xenon octafluoride | *** **What is the CORRECT name for this binary compound CO?** - monocarbon monoxide - **carbon monoxide** - monocarbon oxide - carbon oxide *** ## 11. Represents the chemical reaction using a balanced chemical equation, including the symbols of elements, compounds, and their physical states **Text book + table 1+fiqure3+ example Problem1 + practice problems** *** ### Table 1 Symbols Used in Chemical Equations | Symbol | Meaning | |---|---| | → | produces or yields | | + | plus | | (s) | solid | | (l) | liquid | | (g) | gas | | (aq) | aqueous–a substance is dissolved in water| | heat, | The reactants are heated.| | light | The reactants are exposed to light. | | elec., | An electric current is applied to the reactants. | *** **Consider the following equation:** Hydrogen gas + chlorine gas → hydrochloric acid **What are the substances present at the start of a chemical reaction called?** - **reactants** - coefficients - products - equations *** **BALANCE EQUATIONS** A sample of barium sulfate (BaSO₄) is placed on a piece of paper, which is then ignited. Barium sulfate reacts with the carbon (C) from the burned paper, producing barium sulfide (BaS) and carbon monoxide (CO). Write a balanced equation for this reaction. *** **PRACTICE Problems** - Balance this equation: MgCl₂(aq) + AgNO₃(aq) → Mg(NO₃)₂(aq) + AgCl(s). - Balance this equation: NaOH(aq) + CaBr₂(s) → Ca(OH)₂(s) + NaBr(aq). - HCI is slowly added to aqueous Na₂CO₃, forming NaCl, H₂O, and CO₂. Write a balanced equation for this reaction. - Write the balanced equation for the reaction of hydrogen gas and oxygen gas that forms water. *** ## 12. Understand chemical equations in terms of moles, masses, and particles **Text book + table 2** *** Because the number of particles involved in most chemical reactions is so large, chemists use a counting unit called the mole (mol). One mole is the amount of a substance that contains 6.02 × 10²³ particles of that substance. The reaction between one mole of carbon and one mole of oxygen, yielding one mole of carbon dioxide, is summarized in Table 2. ### Table 2 Moles, Mass, and Particles | Equation | C(s) + O₂(g) → CO₂(g) | |---|---| | Number of moles | 1 1 1 | | Mass | 12.01 g 32.00 g 44.01 g | | Number of particles | 6.02 × 10²³ atoms 6.02 × 10²³ molecules 6.02 × 10²³ molecules | *** **In the reaction described, what is the number of particles in one mole of carbon dioxide (CO₂) produced?** - 3.01 × 10²³ molecules - 1.20 × 10²⁴ molecules - **6.02 × 10²³ molecules** - 2.00 × 10²⁴ molecules **When one mole of carbon (C) reacts with one mole of oxygen (O₂), what is produced?** - Two moles of carbon dioxide (CO₂) - **One mole of carbon dioxide (CO₂)** - One mole of carbon monoxide (CO) - Two moles of carbon monoxide (CO) *** ## 13. Calculate the number of moles present in a mass given in grams **Text book** *** **1. How many moles in 67.5 grams of water (H₂O) [Molar mass = 18 g/mol]** - 2.46 mol - **3.75 mol** - 1.35 mol - 4.77 mol **2. How many moles in 35.2g of carbon dioxide (CO₂). [Molar mass = 44.01 g/mol]** - 0.8 mol - 3.7 mol - **1.5 mol** - 8.7 mol The molar mass of carbon is 12.01 g/mol. The mass of 0.5 mol of carbon is equal to **6.005 g.** *** ## 14. Classify chemical reactions according to their type **Text book** *** ### 1. Combustion CH₄(g) + 2O₂(g) → CO₂(g) + 2H₂O(g) *burning methane* C(s) + O₂(g) → CO₂(g) *burning coal* *** ### **2. Synthesis:** H₂(g) + Cl₂(g) → 2HCl(l) CaO + CO₂ → CaCO₃ *** ### 3. Decomposition AB → A + B *decomposition general equation* 2H₂O₂(l) → O₂(g) + 2H₂O(l) 2KCLO₃ → 2KCl + 3O₂ *** ### 4. A single placement Cu(s) + 2AgNO₃(aq) → Cu(NO₃)₂(aq) + 2Ag(s) *** ### 5. A double-displacement AB + CD → AD + CB *** **Which of the following is not a combustion reaction?** - 2Mg + O₂→2MgO - **2H₂O→ 2H₂ + O₂** - C+O₂→ CO₂ - CH₄+2O₂ → CO₂ + 2H₂O **Indicate the type of this chemical reaction:** 2AgNO₃ + Na₂CrO₄ → Ag₂CrO₄ + 2NaNO₃ - **double-replacement reaction** - decomposition - synthesis - single-replacement reaction *** ## 15. Predict whether a chemical reaction will occur using the activity series **Text book+ fiqure 10** *** ### Metals | Most active | Least active | |---|---| | Lithium | Gold | | Potassium | Platinum | | Calcium | Silver | | Sodium | Copper | | Aluminum | Lead | | Manganese | Tin | | Zn | Iron | | Iron | Nickel | | Tin | Manganese | | Lead | Aluminum | | Copper | Calcium | | Silver | Sodium | | Platinum | Potassium | | Gold | Lithium | *** **Refer to the activity series of metals. Which of the following reactions will NOT occur?** - K(s) + H₂O(l) → - Ag (s) + Cu(NO₃)₂(aq) → - Na (s) + AlF₃(aq) → - **Mg (s) + 2HNO₃(aq) →** *** **Using the reactivity series of metals, what would yield the single replacement reaction of calcium (Ca) with zinc nitrate Zn(NO₃)₂?** - Ca (s) + Zn(NO₃)₂ (aq) → - **NR, No Reaction / لن يحدث تفاعل** - Zn (s) + Ca(NO₃)₂ (aq) - Zn(NO₃)₂ (aq) + Ca(OH)₂ (aq) - CaCl₂ (aq) + Zn (s) *** ## 16. Give examples of exothermic and endothermic reactions **Text book** *** ### Q16: Exothermic reaction: It releases heat energy ### Q17:Exergonic reaction: It releases FREE energy **Examples:** - The combustion of rocket fuel - Iron rusting - Wood burning - Burning fuel (coal, petrol, natural gas) to produce electricity - Hot pack - the light emitted by a glow stick - exploding dynamite - The abdomen of a firefly glows *** ### Endothermic reaction: It absorbs heat energy ### Endergonic reaction: It absorbs FREE energy - Water is stable, but the addition of an electrical current will cause it to decompose into hydrogen and oxygen. - 2Al₂O₃(l) elec: 4Al(l) + 3O₂(g) - Cold pack: Epsom salt and water - baking soda decomposition *** ## 17. Differentiate between exergonic and endergonic reactions in terms of the energy released or absorbed by the reactio **Text book + fiqures 15&17** *** **Which of the following is an example of endothermic reaction?** - A. Iron rusting - B. Wood burning - **C. Cold pack** - D. Hot pack **Which of the following statements is correct regarding the following diagrams?** - Diagram A represents exothermic reaction where energy is absorbed - Diagram A represents endothermic reaction where energy is absorbed - **Diagram B represents exothermic reaction where energy is absorbed** - Diagram B represents endothermic reaction where energy is absorbed **Which of the following occurs during an exothermic reaction?** - **thermal energy is released to the surroundings** - the temperature of the surroundings decreases - thermal energy is absorbed from the surroundings - light is absorbed from the surroundings **The following are examples of exergonic reactions EXCEPT** - **cold pack** - cellular respiration - rusting - heat pack **Which of the following best describes an exergonic reaction?** - it releases electric energy only - **it releases free energy** - it releases light energy only - it decreases the surrounding's temperature *** ## 18. Show the effect of the concentration of reactants on the rate of a chemical reaction **Text book+ fiqure 19** *** **1. Concentration:** (mol/L) The more concentrated acid solution contains more reacting particles per unit volume, resulting in more opportunities for collisions between reacting particles. As a result, the reaction rate is greater. **Regarding the figure above, which of the following statements is CORRECT?** - **A. Figure A: high concentration so high reaction rate.** - B. Figure A: low concentration so low reaction rate - C. Figure B: high concentration so low reaction rate - D. Figure B: low concentration so high reaction rate *** **What is the effect of doubling the concentration of a reactant on a chemical reaction?** **Select 2 choice(s)** - **increases the collision between reactants** - **increases the rate of reaction** - decreases the collision between products - decreases the collision between reactants - increases the volume of the reaction mixture - doesn't affect the rate of reaction As the consumption of a certain reactant increases, its concentration decreases thus the rate of the reaction **decreases.** *** ## 19. Explain the effect of the volume and pressure for a chemical reaction involving gases on the rate of a chemical reaction **Text book+ fiqure 20** *** Volume and pressure: More importantly, the reaction rate increases as well because the reacting gas particles collide with each other more frequently. **Regarding the figure above, which of the following statements is CORRECT?** - Increasing pressure will decrease collisions so the rate of the reaction decreases - **Increasing pressure will increase collisions so the rate of the reaction increases** - Increasing volume will decrease collisions so the rate of the reaction increases - decreasing volume will increase collisions so the rate of the reaction increases The following factors increase the collision between particles **EXCEPT increasing the concentration of reactants** - surface area of reactants - pressure of reactants - available volume for reactants ## 20. Describe when a reacting system reaches a state of chemical equilibrium **Text book** *** 2KCIO₃(s) → 2KCI(s) + 3O₂(g) **The single arrow refers to one way reaction** A reversible reaction is one that can occur in both the forward and reverse directions. **Equilibrium** is when a reversible reaction's forward and reverse reactions take place at the same rate. reactants products CO₂(aq) ⇌ CO₂(g) **The following reversible reaction reaches the equilibrium state when:** - **B. Forward rate (1) is equal backward rate (2)** - A. Forward rate (1) is greater than backward rate (2) - C. Forward rate (1) is smaller than backward rate (2) - D. Forward rate (1) is double backward rate (2) N₂(g) + 3H₂(g) ⇌ 2NH₃(g) *** ## 19. Explain the effect of the volume and pressure for a chemical reaction involving gases on the rate of chemical reaction. **Text book+ fiqure 20** *** Volume and pressure: More importantly, the reaction rate increases as well because the reacting gas particles collide with each other more frequently. ## 20. Describe when a reacting system reaches a state of chemical equilibrium **Text book** *** 2KCIO₃(s) → 2KCI(s) + 3O₂(g) *The single arrow refers to one way reaction* A reversible reaction is one that can occur in both the forward and reverse directions. **Equilibrium** is when a reversible reaction's forward and reverse reactions take place at the same rate. *reactants ⇌ products* CO₂(aq) ⇌ CO₂(g) **The following reversible reaction reaches the equilibrium state when:** - **B. Forward rate (1) is equal to backward rate (2)** - A. Forward rate (1) is greater than backward rate (2) - C. Forward rate (1) is smaller than backward rate (2) - D. Forward rate (1) is double backward rate (2) N₂(g) + 3H₂(g) ⇌ 2NH₃(g) ## Characterize each reaction by determining its reaction type. *** a. CaO(s) + H₂O(l) → Ca(OH)₂(aq) *Synthesis* b. Fe(s) + CuSO₄(aq) → FeSO₄(aq) + Cu(s) *Single Replacement* c. C₁₀H(I) + 12O₂(g) → 10CO₂(g) + 4H₂O(g) *Combustion* d. NaCl(aq) + AgNO₃(aq) → NaNO₃(aq) + AgCl(s) *Double Replacement* e. NH₄NO₃(s) → N₂O(g) + 2H₂O(g) *Decomposition* **Which of the following is a single displacement reaction?** - C₃H₈(g) + 5O₂(g) → 3CO₂(g) + 4H₂O(l) - **Cu(s) + 2AgNO₃(aq) → 2Ag(s) + Cu(NO₃)₂(aq)** - 2H₂(g) + O₂(g) → 2H₂O(l) - 2NaOH(aq) + CaBr₂(aq) → Ca(OH)₂(s) + 2NaBr(aq) **What is the type of the following chemical reaction?** SiO₂(s) + 4HF(aq)→SiF₄(s) + 2H₂O(l) - **Dissociation** - Synthesis - Single replacement - Double replacement **Which one of the following chemical reaction equations represents a synthesis reaction?** - 2KCl (s) + 3O₂ (g) → 2 KCIO₃ (s) - C₅H₁₂ (€) + 8O₂ (g) → 5CO₂ (g) + 6H₂O (€) - 2Al(NO₃)₃ (aq)+ 3H₂SO₄ (aq) → Al₂(SO₄)₃ (aq) + 6HNO₃ (aq) - **2Pb(NO₃)₂ (s) → 2PbO (s) + 4NO₂ (g) + O₂ (g)** **What is the type of chemical reaction represented in the equation below?** AB → A + B - *Decomposition reaction* - Combustion reaction - Double Replacement reaction - Single Replacement reaction