The physical states of matter

2. liquids gases solids The physical states of matter At normal temperature almost all substances exist in one of three physical states:

3. Look at the following substances. Decide whether they exist as a solid, liquid or gas. butter oxygen bleach tree orange juice ice lolly cloud perfume desk shampoo coal steam

4. Aluminium, argon, ethanol (alcohol), iron, lead, mercury, radium, tin Match each substance to the correct column in the table. When you have got it all correct the first letter of each substance will spell a word that is important in this unit. Mercury Aluminium Tin Ethanol Radium Iron Argon Lead

5. The existence of solids, liquids and gases is explained by the kinetic theory. This is based on the following ideas: All substances are made up of particles (atoms, ions and molecules). That these particles are attracted to each other, some strongly and others weakly. That these particles move around (i.e. have kinetic energy). That their kinetic energy increases with temperature. Kinetic Theory

6. Particle arrangements: solids This animation shows a 2-D view of the motion of the atoms in a 3-D solid.

7. Particle arrangements: liquids This animation shows a 2-D view of the motion of the atoms in a liquid. There is no order.

8. Particle arrangements: gases

11. Diffusion is the movement of one type of particle into and through another. For example, the smell of after-shave or perfume diffuses across a room. Insects communicate by smells that diffuse through the air. Diffusion 1 • Can you explain these facts? • Diffusion occurs both in liquids and gases but hardly at all in solids. • It happens more quickly for gases than for liquids. • It happens more quickly at warm temperatures than at cooler temperatures.

12. Diffusion 2

13. Here is the result of a simple experiment in which two gases diffuse towards each other in a glass tube. When they meet they react to form a cloud of smoke. Diffusion 3 Cotton wool soaked in hydrochloric acid (concentrated) Cotton wool soaked in ammonia solution The smoke forms nearer to one end than the other. Which particles are moving faster: ammonia or acid? Can you suggest a possible reason for this? Ammonia particles are lighter and so, at any given temperature, move faster.

14. Across: 2 Change from liquid to solid 5 Force caused by collisions of particles 6 Arranged in a 3 dimensional pattern 9 Spacing of particles in solids and liquids 10 All substances are this state at very low temperatures 11 Only liquids and gases do this 1 2 3 4 5 6 7 8 9 10 11 Crossword Down: 1 "Heavy“ 3 Change from gas to liquid 4 Change from solid to liquid 6 State with particles close but disorganised 7 Particles widely spread out 8 Change from liquid to gas

15. 1. Which of the diagrams represents a liquid evaporating? B A D C

16. A compressible, fluid B non-compressible, fluid C compressible, no fixed shape D non-compressible, very low density 2. Which of the following describes a liquid?

17. 3. Which of these is only true for a gas? • A can flow • B exerts pressure on its container • C will occupy the whole of the container it is placed in • D has no shape of its own