Reversible reactions

Cards (28)

  • Chemical reactions are reversible and may reach a dynamic equilibrium.
  • The position of equilibrium of a reversible reaction can be altered by changing the reaction conditions.
  • Reversible reactions involve products that can react together to produce the original reactants.
  • These reactions are called reversible reactions.
  • Reversible reactions can be represented in the following way: A + BC + D.
  • Reversible reactions can be represented in equations: the forward reaction is the one that goes to the right and the backward reaction is the one that goes to the left.
  • The reaction mixture may contain reactants and products, and their proportions may be changed by altering the reaction conditions.
  • Ammonium chloride is a white solid that breaks down when heated, forming ammonia and hydrogen chloride.
  • The balanced chemical equation for the breakdown of ammonium chloride is: NH 4 Cl(s) ⇌ NH 3 (g) + HCl(g).
  • If a reaction is exothermic, it will give out energy to the surroundings, increasing the temperature.
  • If a reaction is endothermic, it will take in energy from the surroundings, decreasing the temperature.
  • The same amount of energy is transferred in both the forwards and reverse reaction.
  • Blue copper sulfate is described as hydrated copper sulfate, containing water of crystallisation, which can be removed by heating strongly.
  • A copper ion is an electrically charged particle, formed when an atom or molecule gains or loses electrons in its crystal lattice.
  • The crystal lattice is the regular arrangement of particles (atoms, molecules or ions) in a crystal.
  • A molecule is a collection of two or more atoms held together by chemical bonds.
  • Water is driven off when blue hydrated copper sulfate is heated, leaving white anhydrous copper sulfate.
  • The reaction of hydrated copper sulfate with water is reversible: hydrated copper sulfateanhydrous copper sulfate + water.
  • The forward reaction of hydrated copper sulfate with water is endothermic and the reverse reaction is exothermic.
  • When a reversible reaction happens in a closed container, it reaches a dynamic equilibrium.
  • In chemical reactions, a situation where the forward and backward reactions happen at the same rate, and the concentrations of the substances stay the same.
  • At equilibrium: the forward and backward reactions are still happening the forward and backward reactions have the same rate of reaction the concentrations of all the reacting substances remain constant.
  • Nitrogen reacts with hydrogen to produce ammonia: N 2 (g) + 3H 2 (g) ⇌ 2NH 3 (g).
  • The balanced equation for the backward reaction of nitrogen reacting with hydrogen is 2NH 3 (g) → N 2 (g) + 3H 2 (g).
  • Changing the position of equilibrium in a chemical reaction can be done by changing the concentration, temperature, or pH.
  • Rates of reaction are important in understanding the rate and extent of chemical change.
  • AQA offers sample exam questions on the rate and extent of chemical change.
  • The BBC offers a variety of resources on science, including Earth, Reel, Worklife, and Culture.