<<

States of Unit

Learning Target Notes Section 1: Matter and What makes up matter? Matter is made of and that are in constant motion. Kinetic Theory of Matter A. Particles that make up matter are in constant motion. B. The higher the , the faster the particles move. C. At the same temperature, more massive particles move slower than less massive particles. What is the difference between a , a , Solid – has definite shape and and a ? Liquid – has definite volume, but not definite shape Gas – changes both volume and shape

The difference between a solid, a liquid, and a gas is and don’t change volume, but do.

Plasma – no definite volume or shape; electrically charged state of matter (ionized); examples: , fire, the Sun… What kind of energy do all particles of matter have? Temperature is a measure of average kinetic energy.

Thermal energy – TOTAL kinetic energy; dependent on particle speed and number of particles.

States of Matter Unit

Section 2: Changes of State What happens when a substance changes from The identity of the substance doesn’t change, but one state of matter to another? the energy of the substance does change.

Freezing – Energy is released (liquid -> solid) – Energy is absorbed (solid -> liquid) – Energy is released (gas -> liquid) – Energy is absorbed (liquid -> gas) Sublimation – Energy is absorbed (solid -> gas) Deposition – Energy is released (gas -> solid)

Temperature is constant during change of state.

**You need to know the diagram at the bottom of page 84 What happens to mass and energy during physical Mass and energy are both conserved. and chemical changes? NEITHER MASS OR ENERGY CAN

BE CREATED OR DESTROYED!

Law of Conservation of Mass Law of Conservation of Energy

States of Matter Unit

Section 3: How do fluids exert ? Pressure – the amount of force exerted per unit area of a surface (Chapter 2): a nonsolid state of matter in Fluids exert pressure evenly in all directions. which the atoms or molecules are free to move past one another, as in a liquid or a gas. P = F/A (Pressure = Force divided by Area) SI unit: pascal (1 N/m2)

What is buoyant force? All fluids exert an upward buoyant force on matter.

-The upward force that keeps an object immersed in or floating on a liquid.

Archimedes’ Principle The buoyant force on an object in a fluid is an upward force equal to the weight of the fluid that the object displaces.

An object will float or sink based on its density and surface area. What happens when pressure in a fluid changes? Pascal’s Principle A change in pressure at any point in an enclosed fluid will be transmitted equally to all parts of the fluid.

푃1 = 푃2

퐹1 퐹2 = 퐴1 퐴2

(Hydraulic devices are based on Pascal’s Principle.) What affects the speed of a fluid in motion? Fluids move faster through small areas than through larger areas, if the overall flow rate remains constant. Fluids also vary in the rate at which they flow.

Viscosity – the resistance of a gas or liquid to flow  Dependent on particle attraction  The more attracted the particles are the slower (more viscous) a fluid is. (Ex: Honey)

Fluid pressure decreases as speed increases.  Bernoulli’s Principle – as the speed of a moving fluid increases, the pressure of the moving fluid decreases

States of Matter Unit

Section 4: Behavior of Gases What are some properties of gases? Gases expand to fill their containers. They spread out easily and mix with one another. They have low densities and are compressible. They are mostly empty space. Gases exert pressure on their containers. How can you predict the effects of pressure, GAS LAWS temperature, and volume changes on gases? 1. Boyle’s Law – relates pressure to volume

At constant temperature, the volume of a gas increases as the gas’s pressure decreases. If the volume decreases, the pressure increases.

Inverse relationship – curved graph

2. Gay-Lussac’s Law – relates pressure to temperature

Pressure of a gas increases as the temperature increases. The pressure decreases as the temperature decreases.

Direct relationship – straight-line graph

3. Charles’s Law – relates temperature to volume

At a constant pressure, volume of a gas increases as the temperature increases. If the volume decreases, the temperature decreases.

Direct relationship – straight-line graph Mathematical Formulas of Gas Laws Boyle’s Law 푃1푉1 = 푃2푉2

푃 푃 Gay-Lussac’s Law 1 = 2 푇1 푇2

푉 푉 Charles’s Law 1 = 2 푇1 푇2 The Law The relates the variables of pressure, volume, temperature, and number of moles of gas within a closed system. Conversions

K = °C + 273 3 PV = nRT 1 cm = 1 mL 3 1 dm = 1 L = 1000 mL P = pressure of the confined gas (unit: atm)

V = volume of the confined gas (unit: L) Standard Conditions n = number of moles of gas 0°C = 273 K R = gas constant (0.0821 L atm/mol K) 1 atm = 760 mm Hg = 101.325 kPa = 101,325 Pa T = temperature (unit: K)

States of Matter Unit