Predicting a physical state - Earth's atmosphere - GCSE Chemistry (Single Science) Revision - OCR 21st Century - BBC Bitesize

Predicting a physical stateThe state of a substance at a given temperature can be predicted if its melting point and boiling point are known.QuestionThe melting point of oxygen is -218°C and its boiling point is -183°C. Predict the state of oxygen at -200°C.Explaining melting points and boiling pointsMeltingParticles in a substance have forces of attraction between them. When a substance in the solid state is heated:energy is transferred to the particles the particles move faster and have more some of the bonds are overcome and particles can slide round each otherBoilingenergy is transferred to the particles particles eventually gain enough kinetic energy to overcome the forces of attraction the particles can then move apartThe strength of the forces of attraction between particles varies between substances.The stronger the forces of attraction between particles, the more energy is needed to overcome them, and so the higher the boiling point and the higher the melting point.Condensing...