Year 11 Chemistry Topic Test - Rotation 2, 2024 PDF

# Year 11 Chemistry Topic Test - Rotation 2, 2024 ## Section A: Multiple Choice Questions ### Question 1 Calcium carbonate reacts with hydrochloric acid to form carbon dioxide. Which changes would slow this reaction down? * Decreasing the concentration of hydrochloric acid. * Decreasing the part...

# Year 11 Chemistry Topic Test - Rotation 2, 2024 ## Section A: Multiple Choice Questions ### Question 1 Calcium carbonate reacts with hydrochloric acid to form carbon dioxide. Which changes would slow this reaction down? * Decreasing the concentration of hydrochloric acid. * Decreasing the particle size of calcium carbonate. * Decreasing the temperature. **Answer:** D - 1, 2 and 3 ### Question 2 A compound with the formula XF₂ has a relative formula mass of 78. What is element X? * Argon * Calcium * Neon * Zirconium **Answer:** B - Calcium ### Question 3 Petroleum is a very important raw material that is separated into more useful products. Which terms describe petroleum and the method used to separate it? | Petroleum is a | Method used to separate petroleum | |---|---| | A. Compound | Cracking | | B. Compound | Fractional Distillation | | C. Mixture | Cracking | | D. Mixture | Fractional Distillation | **Answer:** D - Mixture, Fractional distillation ### Question 4 Skin cancer can be treated using a radioactive isotope of phosphorus, ³²P. A compound containing the phosphide ion, ³²P⁻³, wrapped in a plastic sheet, is strapped to the affected area. What is the composition of the phosphide ion, ³²P⁻³? | Protons | Neutrons | Electrons | |---|---|---| | A. 15 | 17 | 18 | | B. 15 | 17 | 32 | | C. 17 | 15 | 17 | | D. 32 | 17 | 15 | **Answer:** C - 17, 15, 17 ### Question 5 The proton number of helium is 2. What information does this give about helium? * Its atom has two electrons. * Its atom is twice as heavy as a hydrogen atom. * It is a Group II element. * Its molecule has two atoms. **Answer:** A - Its atom has two electrons. ### Question 6 The equation shows the reaction that occurs when ethanol burns in air. C₂H₅OH + xO₂ → yCO₂ + zH₂O Which values of x, y and z are needed to balance this equation? | x | y | z | |---|---|---| | A. 2 | 2 | 2 | | B. 2 | 2 | 3 | | C. 2 | 3 | 3 | | D. 3 | 2 | 3 | **Answer:** B - 2, 2, 3 ## Section B: Structure Questions ### Question 1 The alkanes are a family of saturated hydrocarbons. * Circle 2 isomers from the molecules shown below: (Diagram is not included in this output. Replace with the correct image.) * State the general name given to unsaturated-hydrocarbons like those shown in 1(a)? * Demand for short chain hydrocarbons, such as those used in a car are in much higher demand than longer chain hydrocarbons. Name the process by which long chain hydrocarbons are split into shorter chain hydrocarbons. * Many of the compounds obtained from petroleum are alkanes. (Diagram is not included in this output. Replace with the correct image.) Which chemical is used to distinguish compound B from compound A and D? AND What color change is observed? **Answers:** * The 2 isomers in the diagram should be circled. * Alkene. * Cracking. * Bromine water. **Observation:** * Compound B will turn the bromine water from orange-brown to colorless. * Compounds A and D will remain orange-brown. ### Question 2 * Ammonium chloride is commonly produced in a science class to show diffusion. How many atoms are there in the formula NH₄Cl? * Which of the following has a relative formula mass closest to 62? * Sodium chloride, NaCl * Potassium bromide, KBr * Magnesium fluoride, MgF2 * Sodium bromide, NaBr * If you had 25g of baking soda, Na₂CO₃. How many moles would you have? Use the resource sheet. * What is the % composition (by mass) of sodium in baking soda, Na₂CO₃? Use the molar mass from 2(c). **Answers:** * 5 * B - Potassium bromide, KBr * 0.24 moles * 43.4% ## Question 3 * A compound contains 10.1% aluminium and 89.9% bromine by mass. Calculate the empirical formula of this compound. Show ALL working. * A scientist finds a sample of white powder while clearing out a cupboard in the lab. The label on the container says that it contains 0.075 moles of an unknown metal oxide. The sample weighs 3.0 g. Calculate the molar mass of the metal oxide. * 14 g of calcium chloride was dissolved in 80 ml of water. Calculate the concentration of the solution and give the units. The relative molecular mass for calcium chloride (CaCl₂) is 111 g mol⁻¹. * What mass of calcium oxide is formed when 40 g of calcium carbonate is completely reacted? * The molar mass of calcium carbonate (CaCO₃) is 100 g/mol, the molar mass of calcium oxide (CaO) is 56 g/mol. * CaCO₃ → CaO + CO₂ * A sample of magnesium was analysed and found to consist of three isotopes, magnesium -23, 24 and _25_. (Diagram is not included in this output. Replace with the correct image.) Calculate the relative atomic mass of the sample of magnesium. Give answer to 2 decimal places. **Answers:** * AlBr₃ * 40 g/mol * 1.75 mol/L * 22.4 g * 24.32 ## NCEA Question: A volcano simulation can be made by carrying out a home science experiment. The experiment uses an acid-carbonate reaction. * The instructions suggest that cold acidic vinegar should be used. Use collision theory to explain what would happen if warm vinegar was used, rather than cold vinegar. * The experiment was repeated in a school lab, and the carbon dioxide gas produced was collected until no more gas was being produced. (Diagram is not included in this output. Replace with the correct image.) Explain what is happening in sections A, B, and C of the graph. You should link the rate of reaction in each section to the gradient of the line and particle collisions. * A different home volcano kit suggests adding water to the vinegar. When this is tried, the reaction is slower. * Identify the factor affecting the reaction rate being investigated in this experiment. * Use collision theory to explain this result. Link your answer to particle collisions. **Answers:** * The particles in the warm vinegar will have more kinetic energy, which means they will move faster and collide more frequently with the particles of the bicarbonate. This will lead to a greater number of successful collisions between the reactant particles, resulting in a faster rate of reaction. * * **Section A:** The rate of reaction is high, indicated by the steep gradient of the line. This is because the concentration of the reactants is high, leading to a high frequency of collisions. * **Section B:** The rate of reaction slows down, shown by the less steep gradient. This is because the concentration of reactants decreases as carbon dioxide gas is produced. As the frequency of collisions decreases, the rate of reaction slows down. * **Section C:** No more carbon dioxide is being produced, indicated by the horizontal line. The rate of reaction is zero, and there are no successful collisions taking place, meaning the reaction has stopped. * * The factor being investigated is the concentration of the acetic acid in the vinegar. * * Dilution of the vinegar will decrease the concentration of acetic acid. This means that there are fewer particles of acetic acid per unit volume, leading to fewer collisions. * As a result, the rate of reaction will be slower.