Combined Science Double Award - 9204 OxfordAQA

Preparation Of Salts

Resumen

Somewhere in the building you are sitting in there is almost certainly a bag of plaster, a tub of bath salts, a fertiliser sack or a packet of baking powder. Every one of them is a salt, and every one of them was made on purpose by a chemist who first had to answer a deceptively small question: does the thing I am trying to make dissolve in water or not? That single answer decides everything else. It chooses the starting materials, it chooses the apparatus, and it decides whether the product arrives as crystals grown slowly from a warm liquid or as a cloudy solid that appears in a fraction of a second the instant two clear solutions meet.

This lesson gives you the whole decision tree and then walks each branch of it in detail. You will learn how to sort a salt into soluble or insoluble before you touch a single bottle, the three acid routes to a soluble salt and why a route that works beautifully for copper would be dangerous for sodium, the reason chemists deliberately add too much of one reactant and then throw the leftovers away, and the patient technique that turns a colourless solution into a dish of grown crystals. By the end you will be able to plan a preparation for a salt you have never made, which is precisely what your specification asks of you and precisely what the chemistry paper sets.

Objetivos

  1. Soluble salts can be made from acids by reacting them with: metals - not all metals are suitable; some are too reactive and others are not reactive enough; insoluble bases - the base is added to the acid until no more will react and the excess solid is filtered off; alkalis - an indicator can be used to show when the acid and alkali have completely reacted to produce a salt solution. Students should be able to suggest methods to make a named soluble salt.
  2. Salt solutions can be crystallised to produce solid salts.
  3. Insoluble salts can be made by mixing appropriate solutions of ions so that a precipitate is formed. Precipitation can be used to remove unwanted ions from solutions: for example, in treating water for drinking or in treating effluent. Students should be able to name the substances needed to make a named insoluble salt.

Mapa mental

Este tema esta esquematizado para ver como se conectan las ideas.

Abre el mapa mental en la app

Nota de la lección

A salt is what remains when the hydrogen of an acid has been handed over to a metal, or to the ammonium group, and something else has carried the hydrogen away. Sodium chloride is a salt. So are the calcium sulfate in a plaster cast, the ammonium nitrate spread on a field, the copper(II) sulfate that stains a school beaker blue, and the barium sulfate a patient swallows before an abdominal scan. The name of any one of them is assembled from two parts, and both parts are chosen for you by your starting materials: the metal at the front comes from whatever you neutralise the acid with, and the family name at the back comes from the acid itself. The topic before this one, The properties of acids and bases, is where those naming rules and the meaning of neutralisation belong, so this lesson takes them as read and gets on with the apparatus.

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.

Notas de lección completas con diagramas
Asistente de aprendizaje con IA
Simulacros cronometrados que se corrigen en cuanto terminas
Disponible en Android, Windows, macOS y Linux App para iOS proximamente

Evaluación de la lección

Felicitaciones por completar la lección del Preparation Of Salts. 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.

  1. Which salt is produced when copper(II) oxide reacts with dilute nitric acid? A. copper(II) nitrate B. copper(II) sulfate C. copper(II) chloride D. copper(II) carbonate Answer: A
  2. Which of these salts is insoluble in water? A. sodium carbonate B. potassium sulfate C. barium sulfate D. zinc nitrate Answer: C
  3. A student adds excess magnesium oxide to warm dilute hydrochloric acid, then filters the mixture. What passes through the filter paper? A. magnesium oxide only B. magnesium chloride solution C. hydrochloric acid only D. solid magnesium chloride Answer: B
  4. Which pair of solutions would produce a precipitate of silver chloride? A. silver nitrate and sodium nitrate B. sodium chloride and potassium nitrate C. silver nitrate and sodium chloride D. silver chloride and sodium nitrate Answer: C
  5. Why can potassium nitrate not be prepared by adding excess potassium hydroxide to nitric acid and filtering? A. Potassium nitrate is insoluble in water. B. Potassium hydroxide dissolves, so an excess of it cannot be filtered off. C. Nitric acid does not react with potassium hydroxide. D. The reaction produces a gas that must be measured. Answer: B

Resuelve estas preguntas en la aplicacion

Resuelve estas preguntas en la aplicacion

Practica preguntas simuladas

¿Quieres practicar preguntas simuladas sobre Preparation Of Salts? 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.

Green Bridge CBT Mobile App
Asistente de Chat de Aprendizaje Personalizado con IA
Más de 200.000 preguntas de examen de IGCSE, JAMB, WAEC y NECO.
Más de 1200 notas de lecciones
Soporte sin conexión: Aprende en cualquier momento y lugar.
Horario del Puente Verde
Resúmenes de Literatura y Preguntas Potenciales
Controla tu rendimiento y progreso.
Explicaciones detalladas para un aprendizaje integral