L3f",null,{"backHref":"/gcse/chemistry/ocr/questions","basePath":"/gcse/chemistry/ocr/monitoring-chemical-reactions/questions","formulaUrl":null,"initialIndex":24,"initialQuestionWindow":[{"id":"255e3819-98ff-4995-830c-7519df2658f9","revisionId":"f66a649e-9b84-469e-81ac-e80c674046e9","questionNumber":null,"questionType":"LA","specification":"### Part (a)\n\nA student investigates the reaction between calcium carbonate, \$\\text{CaCO}_3\$, and hydrochloric acid, \$\\text{HCl}\$.\n\nCalcium chloride, water, and carbon dioxide are produced.","difficulty":3,"difficultyBand":"easy","totalMarks":6,"sourceTitle":null,"calculatorUse":null,"parts":[{"id":"4a2a2f7e-0530-4d34-8293-b7277902181d","label":"a","content":"Complete the balanced symbol equation for the reaction.\n\n\\[\\text{CaCO}_3(\\text{s}) + 2\\text{HCl}(\\text{aq}) \\rightarrow \\dots\\dots\\dots\\dots\\dots (\\text{aq}) + \\text{H}_2\\text{O}(\\text{l}) + \\text{CO}_2(\\text{g})\\]","markscheme":"- Completes the equation with $\\text{CaCl}_2$ B1","marks":1,"order":0,"markingRubric":null,"explanation":null,"options":[]},{"id":"a92893f7-501a-4e54-adf6-a867d6717f19","label":"b","content":"Hydrochloric acid has the state symbol \$\\text{(aq)}\$.\n\nWhat does \$\\text{(aq)}\$ mean?","markscheme":"- Explains that $\\text{(aq)}$ means aqueous or dissolved in water B1","marks":1,"order":1,"markingRubric":null,"explanation":null,"options":[]},{"id":"7d559d81-fbf4-48dc-a009-efcc69bf258b","label":"c","content":"Name a common piece of laboratory apparatus that can be connected to the reaction flask to collect and measure the volume of carbon dioxide gas produced.","markscheme":"- Names \"gas syringe\" (or inverted measuring cylinder / burette filled with water) B1","marks":1,"order":2,"markingRubric":null,"explanation":null,"options":[]},{"id":"676a0bad-e2d6-4a93-be29-787bf6c7e14c","label":"d","content":"### Part (b)\n\nThe table below shows the student's results during the reaction:\n\n| Time (minutes) | Volume of gas collected (\$\\text{cm}^3\$) |\n| :---: | :---: |\n| 0 | 0.0 |\n| 1 | 8.0 |\n| 2 | 14.0 |\n| 3 | 18.0 |\n| 4 | 21.0 |\n| 5 | 23.0 |\n| 6 | 24.0 |\n| 7 | 24.0 |\n| 8 | 24.0 |\n\nAt what time was the reaction complete?","markscheme":"- Identifies that the reaction is complete at $6\\text{ minutes}$ (when volume remains constant at $24.0\\text{ cm}^3$) B1","marks":1,"order":3,"markingRubric":null,"explanation":null,"options":[]},{"id":"3bc58553-627a-4aa7-b4ec-ac4de9695f6e","label":"e","content":"By drawing a smooth curve of best fit through these data points, estimate the volume of gas collected at \$3.5\\text{ minutes}\$.","markscheme":"- Estimates the volume of gas at $3.5\\text{ minutes}$ to be in the range $19.5\\text{ cm}^3$ to $20.0\\text{ cm}^3$ B1","marks":1,"order":4,"markingRubric":null,"explanation":null,"options":[]},{"id":"06e573b1-909f-49e5-83de-14f1756306ab","label":"f","content":"The student wishes to collect a larger volume of gas. Assuming the calcium carbonate solid is in excess, which of the following changes to the experiment should the student make?\n- Use a larger conical flask\n- Use less calcium carbonate\n- Use more hydrochloric acid\n- Lower the temperature of the acid","markscheme":"- Selects \"Use more hydrochloric acid\" B1","marks":1,"order":5,"markingRubric":null,"explanation":null,"options":[]}],"options":[],"explanation":null,"firstAttemptFullMarks":null},{"id":"342f13a0-266e-40c4-bb65-2b0075332695","revisionId":"13f20408-3bf7-4bff-93d0-80a7fd41fa82","questionNumber":null,"questionType":"MC","specification":"Look at the mass spectrum of a carbon compound.\n\n![Mass spectrum of a carbon compound](https://assets.mathsgenie.co.uk/aqa-qb/377e3179-26fb-4ad6-9abd-9357c7392154.png)\n\nWhich carbon compound is the mass spectrum from?","difficulty":9,"difficultyBand":"easy","totalMarks":1,"sourceTitle":null,"calculatorUse":null,"parts":[],"options":[{"id":"d7446155-ebd9-4c74-a84f-14fd0c59dd01","content":"$$\\text{C}_2\\text{H}_6$","correct":

Monitoring chemical reactions

Question 9

Monitoring chemical reactions Questions

Monitoring chemical reactions

Question 9

Monitoring chemical reactions Questions