Kinetic Theory
Resumen
Stand a pan of crushed ice on a hot ring with a thermometer in it and watch the reading. It climbs to zero and then it stops. The ring is still glowing, the ice is visibly turning to water, joules are pouring in at hundreds every second, and the number on the thermometer refuses to move. It stays there for minutes. Only when the last sliver of ice has gone does the reading start to rise again, and later, at one hundred, it stalls a second time and stays stalled while the pan boils dry. Two flat stretches in one heating, and in both of them energy is arriving with nothing to show for it on the scale.
Nothing has gone missing. This lesson shows you where those joules went, and it hands you a way of reading any temperature against time graph as a story about particles: how far apart they are, how fast they move, and how tightly they are held to each other. You will compare the three states in one model, define specific heat capacity and put numbers into the equation that goes with it, learn to say in words exactly what is happening along a flat section of a graph, find out what impurities do to a melting point and a boiling point, and finish by cooling molten stearic acid in a test tube and watching one of those flat stretches appear in reverse on your own results.
Objetivos
- Kinetic theory can be used to explain the different states of matter and their properties. The particles in solids, liquids and gases have different amounts of energy. Students should be able to recognise, use and compare simple diagrams to represent key features of solids, liquids and gases.
- The specific heat capacity of a substance is the amount of energy required to change the temperature of one kilogram of the substance by one degree Celsius. The relationship between energy, E, mass, m, specific heat capacity, c, and temperature change, ∆θ, is: e.The melting point of a solid and the boiling point of a liquid are affected by impurities. Required practical: Investigate cooling curves for stearic acid. Throughout Section 3.4, students should be able to explain the shape of the temperature-time graph for a substance that is either cooled or heated through changes in state.
Mapa mental
Este tema esta esquematizado para ver como se conectan las ideas.
Abre el mapa mental en la app
Nota de la lección
Apunte completo disponible en la aplicacion Green Bridge
Instala la aplicacion Green Bridge CBT en tu movil u ordenador para acceder a toda la biblioteca IGCSE: examenes anteriores, criterios de correccion, mapas mentales, tarjetas de estudio y lecciones en audio.
Evaluación de la lección
Felicitaciones por completar la lección del Kinetic Theory. Ahora que has explorado el conceptos e ideas clave, es hora de poner a prueba tus conocimientos. Esta sección ofrece una variedad de prácticas Preguntas diseñadas para reforzar su comprensión y ayudarle a evaluar su comprensión del material.
Te encontrarás con una variedad de tipos de preguntas, incluyendo preguntas de opción múltiple, preguntas de respuesta corta y preguntas de ensayo. Cada pregunta está cuidadosamente diseñada para evaluar diferentes aspectos de tu conocimiento y habilidades de pensamiento crítico.
Utiliza esta sección de evaluación como una oportunidad para reforzar tu comprensión del tema e identificar cualquier área en la que puedas necesitar un estudio adicional. No te desanimes por los desafíos que encuentres; en su lugar, míralos como oportunidades para el crecimiento y la mejora.
- Which statement describes the particles in a liquid? A. Held in fixed positions in a regular arrangement B. In contact with one another but free to slide past each other C. Widely separated and moving quickly in random directions D. Widely separated and held in fixed positions Answer: B
- What is the unit of specific heat capacity? A. J B. J/kg C. J/kg/degC D. degC/J Answer: C
- The specific heat capacity of water is 4200 J/kg/degC. How much energy is needed to raise the temperature of 2.0 kg of water from 15 degC to 35 degC? A. 42 000 J B. 84 000 J C. 168 000 J D. 294 000 J Answer: C
- A pure substance is heated steadily and its temperature stays constant for several minutes. Which statement is correct for that period? A. No energy is being transferred to the substance B. The energy transferred is increasing the average speed of the particles C. The energy transferred is separating the particles as the substance changes state D. The energy transferred is being destroyed Answer: C
- Salt is dissolved in a beaker of pure water. What happens to the freezing point and to the boiling point of the water? A. Both are lowered B. The freezing point is lowered and the boiling point is raised C. The freezing point is raised and the boiling point is lowered D. Both are raised Answer: B
Resuelve estas preguntas en la aplicacion
Resuelve estas preguntas en la aplicacion
Libros Recomendados
Practica preguntas simuladas
¿Quieres practicar preguntas simuladas sobre Kinetic Theory? Descarga la aplicación Green Bridge CBT para acceder a preguntas simuladas y evaluaciones completas sobre este tema.
Descarga la aplicación en Google Playstore.
Todo lo que necesitas para destacar en JAMB, WAEC y NECO.
