anation":null,"firstAttemptFullMarks":null},{"id":"e460d478-0a97-41f3-ba05-21a8347e552c","revisionId":"7b0552e5-6f64-48f9-879d-08f19321346b","questionNumber":null,"questionType":"LA","specification":"During a fire-piston demonstration, a piston is swiftly driven down into a sealed cylinder containing a small piece of tinder. The rapid compression of the trapped air ignites the tinder.","difficulty":6,"difficultyBand":"medium","totalMarks":2,"sourceTitle":null,"calculatorUse":null,"parts":[{"id":"ddba1a26-f34b-4384-a203-804d008cb24a","label":null,"content":"Explain, in terms of work done and the motion of gas molecules, why this rapid compression causes the temperature of the air inside the cylinder to rise.","markscheme":"- Explains that work is done on the trapped air by the piston during compression M1\n- Explains that this work done increases the average kinetic energy of the air molecules, which corresponds to an increase in temperature A1","marks":2,"order":0,"markingRubric":null,"explanation":{"methods":[{"id":"particle_energy","label":"Work done on gas","steps":[{"type":"text","order":1,"title":"Identify the energy transfer","content":"As the piston pushes into the **sealed cylinder**, it exerts a force through a distance on the trapped air. That means **work is done on the air** during compression. This earns **M1**.","highlights":[{"text":"swiftly driven down into a sealed cylinder","location":"specification"}]},{"type":"text","order":2,"title":"Link work to particles","content":"The work done transfers energy to the air molecules. Their **average kinetic energy** increases, meaning that on average the molecules move faster.","highlights":[{"text":"rapid compression of the trapped air","location":"specification"}]},{"type":"text","order":3,"title":"Conclude with temperature","content":"Temperature is related to the average kinetic energy of the gas molecules. Therefore, the increased average kinetic energy means the air temperature rises. This is the **A1** point.","highlights":[{"text":"temperature of the air inside the cylinder to rise","location":"specification"}]}]}],"generatedAt":"2026-07-22T11:40:10.133Z","modelVersion":"gpt-5.6-terra+diagrams-1","explanationVersion":"v3"},"options":[]}],"options":[],"explanation":null,"firstAttemptFullMarks":null},{"id":"e660ebd8-c0e0-4b45-8f5a-36f8b30432eb","revisionId":"7a98734a-0100-4d80-a4b6-479de01cd3ad","questionNumber":null,"questionType":"LA","specification":"A student traps a sample of air inside a sealed plastic syringe, as shown in the diagram.\n\n![A diagram of a sealed syringe with a plunger. In the initial state, the plunger is pulled back, enclosing a volume of 80 cm³ of gas at a pressure of 100 kPa. In the final state, the plunger is pushed in, enclosing a volume of 40 cm³ of gas at a pressure of 200 kPa. The gas particles are shown as small, randomly distributed spheres inside the syringe.](https://assets.mathsgenie.co.uk/aqa-qb/8ee35bae-a540-4d43-94af-46d9608851de.png)\n\nThe plunger is pushed in slowly so that the volume of the gas decreases while its temperature remains constant.","difficulty":7,"difficultyBand":"medium","totalMarks":6,"sourceTitle":null,"calculatorUse":null,"parts":[{"id":"9e3dbded-05ab-4202-9891-18c27b24b960","label":null,"content":"Explain, **in terms of gas particles**, why the pressure of the gas increases when the volume decreases.\n\nYour answer should refer to:\n- how the gas particles exert a pressure\n- why the pressure increases when the volume is reduced at a constant temperature.","markscheme":"- Identifies that gas particles are in constant, rapid, random motion and collide with the internal walls of the syringe B1\n- Explains that each collision exerts a force on the wall, and pressure is the total force per unit area ($P = \\frac{F}{A}$) B1\n- States that constant temperature means the average kinetic energy and average speed of the gas particles remain unchanged B1\n- Explains that decreasing the volume increases the number density of particle

Gas pressure and temperature

Question 25

Gas pressure and temperature Questions

Gas pressure and temperature

Question 25

Gas pressure and temperature Questions