states of matter quiz 4-10.pptx

Matter and chemistry definition Matter is anything that has mass and takes up space. All the substances and materials of which the universe is composed of. Chemistry: is the study of the composition, structure, and properties of matter, the processes that matter undergoes, and the...

Matter and chemistry definition Matter is anything that has mass and takes up space. All the substances and materials of which the universe is composed of. Chemistry: is the study of the composition, structure, and properties of matter, the processes that matter undergoes, and the energy changes that accompany these processes. “ How matter behaves and how one kind of 1  Kinetic model All matters are made up of very small particles (atoms, molecules or ions). (Different substances contain different types of particles- such as atoms or molecules). The particles are moving all the time (the higher the temperature, the higher the average energy of particles). In a gas, the faster the particles are moving, the higher the temperature. 2  Kinetic model- cont’d. The freedom of movement and the arrangement of the particles is different for the three states of matter. The pressure of a gas is produced by the atoms or molecules of the gas hitting the walls of the container. The more often particles collide with the walls, the greater the pressure. 3 4 STATES OF MATTER SOLIDS Particles of solids are tightly packed, vibrating about a fixed position. Solids have a definite shape and a definite volume. Heat 5 STATES OF MATTER LIQUID  Particles of liquids are tightly packed, but are far enough apart to slide over one another.  Liquids have an indefinite shape and a definite volume. Heat 6 STATES OF MATTER GAS  Particles of gases are very far apart and move freely.  Gases have an indefinite shape and an indefinite volume. Heat 7  Fluidity and IMS The ability of the particles to move in the liquid and gas phases produces their fluid properties. The space between the particles can be called the intermolecular space (IMS). In a gas, the IMS is large and can be reduced by increasing the external pressure- gases are compressible. Ex.: Pepsi can 8  Solids, liquids, gases show an increase in volume (an expansion) when the temperature is increased, and a decrease in volume (a contraction) when the temperature is lowered. The volume of a gas at a fixed temperature can easily be reduced by increasing the pressure on the gas. https://www.youtube.com/watch?v=1Jtw8g795Us 9  Comparison Physical Volume Density Shape Fluidity Spaces Arrangem state ent Solid Fixed High Definite Doesn’t No Regular flow Liquid Fixed Moderat No Generall Small Irregular e to definite y flows high shape; easily. Gas Not Low takes Flows Huge fixed; the easily. expands shape of to fill the the contain contain er. 10 STATES OF MATTER PLASMA  A plasma is an ionized gas. A plasma is a very good conductor of electricity and can be artificially generated by heating or subjecting a neutral gas to a strong electromagnetic field.  Plasmas, like gases have an indefinite shape and an indefinite volume. Some places where plasmas are found… 1. Flames 2. Lightning 3. Aurora (Northern Lights) The Sun is an example of a star in its plasma state  Changes in physical state Watch the following video then answer the questions below: https://www.youtube.com/watch?v=xYU7RSoOZ0U 1- State three physical changes. 2- Differentiate between boiling and evaporating. 3- Explain how the ice in the north pole melts during summer. 16 Changes in physical state 17  Why does water evaporates at room temperature? When water boils, the bonds in the water molecule linking the hydrogen and oxygen atom are not broken. During boiling, the intermolecular bonds in water are the ones that get broken, that is the bonds that link the water molecules together. Even at low temperatures, there are some water molecules which have enough energy to escape and that's why evaporation in water can occur at any temperature (yes, even if the water is in ice). When the temperature increases, there are more molecules with higher kinetic energy and thus, more water can evaporate. 18 Don’t forget; The larger the surface area, the faster the liquid evaporates. The warmer the liquid is, the faster it evaporates. A volatile liquid: evaporates easily and has a relatively low boiling point. A decrease in the pressure leads to decrease in boiling point. How does cooking in pressure cooker takes less time? Answer: The increased pressure inside the cooker increases the boiling point of water above 100°C so more cooking is done before the water actually starts to boil. 19 Pure substances A pure substance consists of only one substance; it has no contaminating impurities. A pure substance melts and boils at sharp and definite temperature. Substance Physical state Melting point Boiling at room /°C point /° C temperature (20° C) Oxygen Gas -219 -183 Nitrogen Gas -210 -196 Ethanol Liquid -117 78 Copper Solid 1083 2600 The melting and boiling points of some common chemical substances. 20 Pure substances- Cont’d A substance’s melting and boiling points in relation to room temperature (20° C) determine whether it is usually seen as a solid, a liquid or a gas. If a m.p is below 20°C and the b.p is above 20 °C, the substance will be a liquid in room temperature. (True or false)? Seawater freezes at a temperature below the freezing point of pure water (0 °C) and boils at a temperature above the boiling point of pure water (100 °C). The presence of an impurity means that these changes will be spread over a range of temperatures in each case. The presence of an impurity in a substance: lowers the melting point and raises the boiling point of the substance. 21 Practice Questions Open your text-book p.7 Solve questions 1 to 4. Group work as pairs. Time: 20 mins. Share your answers. 22 Electrical melting-point apparatus 23 24  Heating curve ᾠ In a pure substance such as Naphthalene, while the solid is melting, the temperature stops rising. It will only begin to rise when all the naphthalene has melted. The solid wax is melting over a range of temperatures. (mixture of substances). 25 26 Cooling curve Work in groups of five and plot the following data: Time Temperatur Time Temperature (minutes) e °C (minutes) °C 0 85 50 25 2 80 55 15 5 78 60 15 10 78 65 15 15 78 70 15 20 78 75 10 25 78 80 5 30 70 35 65 40 50 45 40 27 28 Summary When a solid is melted, or a liquid is boiled, the temperature stays constant until the process is complete. The same is true in reverse when a gas condenses or a liquid freezes. Heat energy is needed to change a solid into a liquid, or a liquid into a gas. During the reverse processes, heat energy is given out. 29 Practice Questions Open your text-book p.10 Solve questions 5 to 7. Group work as pairs. Time: 15 mins. Share your answers. 30  Pure Substance and Mixtures Watch the following video then answer the questions below: https://www.youtube.com/watch?v=dggHWvFJ8Xs 1- Define the terms “pure substance” and “mixture”. 2- Compare and contrast physical change and chemical change. 3- Explain how distilled water can be a pure substance. 4- States types of mixtures. 31  Types of mixture Mixture: is a blend of two or more kinds of matter, each of which retains its own identity and properties. mixed together physically can usually be separated Solution is a type of mixtures. Solute: the solid that dissolves in the liquid. Solvent: the liquid in which the solid dissolves Examples: 1. Dissolved gases in oceans 2. Miscible alcohol in water 3. Alloys: liquid metals together. 32 Classifying matter 33  Properties of matter A physical property is a characteristic that can be observed or measured without changing the identity of the substance. melting point and boiling point A physical change is a change in a substance that does not involve a change in the identity of the substance. grinding, cutting, melting, and boiling 34 Cont’d A chemical property relates to a substance’s ability to undergo changes that transform it into different substances A change in which one or more substances are converted into different substances is called a chemical change or chemical reaction. https://www.quia.com/quiz/303980.html?AP_rand=1192490734 https://wordwall.net/resource/55902845/mixtures-and-pure-subst ances 35  Diffusion Spreading of the solute particles throughout the liquid is an example of diffusion. Diffusion of gases is very important for breathing!. Fluids are made up of moving particles. 36 37 Evidence of particles – diffusion experiments Spray air freshener in the corner of a room Evidence of particles – diffusion experiments Particles spread out in all directions Evidence of particles – diffusion experiments Eventually the particles occupy the whole room  Evidence of particles – diffusion experiments Other examples of diffusion include: Smell of frying bacon from a kitchen Leaking of air from inside a balloon Sugar dissolving in a cup of tea Evidence of particles – diffusion experiments Diffusion is the movement of particles from areas of high concentration to areas of low concentration until they are evenly spread. Diffusion depends upon the random movement of particles. Evidence of particles – diffusion experiments Diffusion is the movement of particles from areas of high concentration to areas of low concentration until they are evenly spread. Diffusion depends upon the random movement of particles. Diffusion is slower in liquids than in gases because liquid particles are not as free to move as gas particles. 44 Explanation of diffusion according to kinetic theory: 1. Heavier particles move more slowly than lighter particles at the same temperature; larger molecules diffuse more slowly than smaller ones. 2. The pressure of a gas is the result of collisions of the fast- moving particles with the walls of the container. 3. The average speed of the particles increases with an increase in temperature. 45