Three States of Matter Chapter 3 Section 1

Particles of Matter The states of matter are the physical forms in which a substance can exist. The three most familiar states are solid, liquid, and gas. (Plasma is the 4th state.) Matter is made of tiny particles called atoms and molecules which are always in motion. The way these particles interact helps determine the state of the matter.

Figure 1, Page 66 Figure 1 on page 66 describes the three familiar states of matter in terms of the speed and attraction of the particles. Solids – molecules are highly attracted to each other and vibrate Liquids – molecules are close and slide past each other Gas – little attraction because a lot of motion

Solids Solid – the state in which the substance has a definite shape and volume The attraction between particles is stronger than the particles of the same substance in the liquid or gaseous state. Particles in a solid move, but only vibrate in their place.

Types of Solids Crystalline solid – have a very orderly, 3-D arrangement of particles; particles repeat in a pattern Examples of crystalline solids are iron, diamond, and ice. Amorphous solid – particles do not have a particular arrangement; substance can change shape under certain conditions Examples of amorphous solids are glass, rubber, and wax.

Liquids Liquid – the state in which the substance has a definite volume but no definite shape Particles move fast enough to overcome some of the attraction between them. Molecules slide past each other to take the shape of the container. The shape of a liquid can change, but the volume cannot.

Characteristics of Liquids Surface Tension – a force that acts on the particles at the surface of a liquid Surface tension causes some liquids to form spherical drops and is different in different types of liquids. Viscosity – a liquid’s resistance to flow The stronger the attraction between the molecules of a liquid, the more viscous the liquid is.

Gases Gas – the state of matter that has no definite shape or volume. Particles of a gas move quickly so there is less attraction between the particles. The amount of empty space between gas particles can change depending on the container the gas is in.

Behavior of Gases Chapter 3 Section 2

Temperature Temperature is a measure of how fast the particles in an object are moving. The faster the particles are moving the more energy they have. On a hot day, gas particles move faster than on a cold day. Therefore, there is more pressure on the walls of the container holding the gas when the temperature is high.

Temperature Less gas is needed to fill a balloon in warm temperatures because the particles of the gas have more energy. At cool temperatures particles move slower. To fill a balloon in cool temperatures more gas is needed because the particles of the gas have less energy.

Temperature As external temperatures increase, the gases in a balloon expand and the balloon could pop. When external temperatures decrease, the gases in a balloon condense and the balloon shrinks.

Volume Volume is the amount of space an object takes up. Particles of gas spread out, so the volume of a gas depends on the container the gas is in. Intro to PVT gases

Pressure The amount of force exerted on a given area of surface is pressure. The basketball and beach ball in Figure 2 on page 71 hold the same volume of air. There are more particles inside the basketball colliding with the inside surface of the ball. There is more pressure in the basketball.

Gas Behavior Laws The temperature, pressure, and volume of a gas are linked. Changing one of these factors will change the other two. Gas laws describe the relationships between temperature, pressure, and volume.

Boyle’s Law Boyle’s Law states that for a fixed amount of gas at a constant temperature, the volume of the gas is inversely related to pressure. As the pressure of a gas increases, the volume decreases by the same amount.

Charles’s Law Charles’s Law states that for a fixed amount of gas at a constant pressure, the volume of the gas changes in the same ways that the temperature of the gas changes. Decreasing the temperature of the gas causes the volume of the gas to decrease. Increasing the temperature of the gas causes the volume of the gas to increase.