What is Matter? Definition of “Science” – knowledge; or a system of knowledge gained using the scientific method and concerned with the physical world and its phenomena Science is – MEASURABLE, TESTABLE, REPEATABLE explanations of the natural world we live in and how it works.

What is Matter? Science is NOT – random; supernatural; dealing with anything that cannot be proven “Matter” – the materials that create everything in the universe; solids, liquids, gases, molecules, atoms, subatomic particles, etc. Matter can be seen, touched, measured, manipulated, and changed in form

What is Matter? “I am unique because…” An “intrinsic property” is a special characteristic that is used to identify one type of matter from another. – For instance, we can tell the difference between gold and pyrite, which look very similar, because of their different densities.

More Matter Matter has two primary characteristics – It has MASS (the measurement of how much material an object contains, counted in grams) – It has VOLUME (the measurement of how much space it takes up, counted in Liters or cubic meters)

More Matter Three phases of Matter – Solids: matter in a fixed shape that does not change on its own – Liquids: matter that changes shape to fit the bottom of a container – Gas: has no shape, spreads out evenly to fill a space

Density Density – the ratio of mass per unit of volume; “how tightly or loosely packed together the material is” A pillow and bag of potting soil have the same volume, but the potting soil is packed full of more ‘stuff’. It has a higher density. Same volume but more Mass = more density.

Density Take 30 students, spread them around the edges of the room. Then pack them together in the middle of the room. The amount of students (MASS) stayed the same, but the space used (VOLUME) changed. Spread out they had less density, packed together they had higher density.

Density Columns

Atomic Theory All substances are made of atoms. Atoms are the smallest particles of a type of element – if divided into smaller pieces, it stops being that element. Atoms of the same element are the same. Different elements have different atoms Atoms join to make new substances

Atomic Theory – Table of the Elements

Atomic Theory – Parts and Pieces Atoms are made of three pieces: protons, neutrons, and electrons The protons and neutrons clump together in the nucleus (the center) Electrons speed around the nucleus in ring- like clouds (think Saturn’s rings but much smaller) Protons have a + charge, electrons are -, and neutrons are neutral

Elements Elements are pure substances An element is composed of only ONE type of atom For example, a block of silver that is 100% pure is made up of only silver atoms

Molecules Molecules are made by combining different types of atoms These form a new substance different from the original atoms Water is made of hydrogen and oxygen atoms that have combined to make water molecules Molecules can be broken down into the original atoms

Making Molecules Each ring of electrons can only hold a certain # When that ring fills up, electrons start filling the next ring Any open slots in a ring can be used to bond with another atom by sharing electrons

Molecules

Temperature What is temperature? – A measure of the amount of thermal (heat) energy in a substance What is cold? Can we measure it? Cold does not exist. We cannot measure or create cold.

Temperature (not notes) Hot and cold are adjectives that describe whether the thermal energy is higher or lower than our body temperature (how it feels to us) Ice is cold because its heat energy is lower than our body temperature. Boiling water is hot because it has more thermal energy than a human body.

Temperature Fahrenheit – common system in US, based on ice water and body temperatures, one of the first systems developed. Celsius – metric system based on water’s freezing and boiling points. Kelvin – modern scientific system for measuring extremely low temperatures. 0 degrees Kelvin is when there is 0 thermal energy and all atomic motion stops.

Temperature (not notes) Celsius is used in science almost exclusively (except when Kelvin is used) Celsius is based on water, like much of the metric system Because of the precision and convenience of the metric system, almost all science is done using metric measurements

Temperature and Density Heat does not rise because heat is ENERGY (and energy flows in whatever direction it needs to go from a high concentration area to a lower concentration area until energy levels are balanced.) Something that has been heated MAY rise IF: – The heat increased the volume which… – Decreases the density and… – The new density is LESS THAN the density of the surrounding environment (air, water, whatever)

Temperature and Density Adding Heat adds energy Adding energy causes the atoms and molecules to move around more More movement requires more space (volume)

Phases of Matter Solids – keep their shape regardless of the container Atoms or molecules are tight and neatly packed together. Very little movement is possible Low Energy state

Phases of Matter Liquids change their shape to fit the container and fill from the bottom up Atoms and molecules do not stay in one spot but move around each other Medium Energy state Moderate amount of movement

Phases of Matter Gases have no shape but fill their container completely Atoms and molecules move very quickly all around the volume of the container Very High energy state

Changing Volume to Change Density Object 1 begins with a mass of 25g and volume of 20cm³. What is its density? If it is heated and the volume becomes 26cm³ yet the mass stays 25g, what is the new density? What if we reduced the heat energy of the original object and changed the volume to 17cm³; what is the density then?

Changing Mass to Change Density If a container has a volume of 40ml and it holds 20g of a substance, what is the density? Let’s say another 10g is packed into the same container along with the original 20g. What is the new density? What would the density be if we took away 7g from the original 20g?

Responding to Heat Diagram What happens when You heat something?

Physical vs. Chemical Change Physical Change – a change in a substance’s appearance (color, shape, size, phase) WITHOUT becoming a new substance – Cutting a piece of paper – Shaping clay – Adding dye to food – Boiling water

Physical vs. Chemical Change Chemical change – a change in a substance based on a chemical reaction that CREATES A NEW SUBSTANCE – Burning wood – Combining hydrogen and oxygen to make water – Combining Iron and Carbon to make Steel – ALWAYS involves either a gain or release of energy (burning is a release of energy, making steel requires a gain of energy)

Changing States of Matter Changing states (or phases) of matter requires a change in energy – either an increase or decrease Every substance has specific temperatures at which it changes – Water melts at 0 C – Gallium melts at 30 C

Changing States of Matter MELTING – changing from a solid to liquid FREEZING – changing from liquid to solid These occur AT THE SAME TEMPERATURE, the difference is whether energy is being added or removed

Changing States of Matter BOILING – changing from liquid to gas CONDENSING – changing from gas to liquid These occur AT THE SAME TEMPERATURE, the difference is whether energy is being added or removed

Changing States of Matter melting boiling freezing condensing Adding Energy Losing Energy SOLID LIQUIDGAS

Evaporation Temperature is the AVERAGE energy level of the particles. This means some will have a higher level than the rest.

Evaporation Air particles hitting the surface of the water transfer some of their kinetic energy to the water particles. This gives some particles enough energy to escape

Condensation The opposite of evaporation – particles in the air hit a low energy surface (like a cold can of soda or a mirror) The particle LOSES energy each time it hits When it has lost enough energy, it changes phase to a liquid and gathers on the cold surface that took its energy

Condensation

Conservation of Matter Matter cannot be created or destroyed – it can only change form Matter is made of atoms and molecules: these can break apart and recombine into new substances Atoms can only be “destroyed” in a nuclear reaction – even then they are not destroyed but change into even smaller pieces and into nuclear and radiation energy

Conservation of Matter 100 water molecules have 200 Hydrogen atoms and 100 Oxygen atoms If split into separate gases we see the following: 100 H20  100 Oxy. (gas) Hyd. (gas) The molecules change form but nothing is lost or gained

Conservation of Energy Since Matter is a form of Energy, the same principle is true for Energy Energy cannot be created or destroyed, it can only change form Energy might move or become a different type but it is never created or destroyed

Types of Energy Chemical – food, fuel, gasoline, anything that can burn or be digested, batteries not being used Electrical – batteries, outlets, generators Nuclear – nuclear power plants Radiant (Light) – sunlight, lightbulbs Sound - …sounds…duh Mechanical – moving parts of a machine or body Thermal – heat, nuff said

Pure vs Mixture A “pure” substance has only one type of particle (atoms or molecules) in it – water ( only H2O molecules), 100% pure gold (only gold atoms), Magnesium Sulfide (only magnesium atoms combined with Sulfur atoms ), table salt (only sodium combined with chlorine atoms) A “mixture” has multiple types of substances that can be separated out – concrete, pizza, trail mix, Kool-Aid, salt water

Compounds COMPOUND – a pure substance made of two or more elements that are chemically combined Compounds are PURE because they are only made up of ONE type of molecule Compounds are NOT mixtures because mixtures can be separated by physical means and compounds cannot. See chart on pg 92 to compare the two

Compounds: 3 Main Characteristics Every compound can be broken down into simpler substances – compounds can only be created or broken down through chemical reactions Every compound has a unique set of Properties that are different from the elements that make it – sodium is explosive, chlorine is poison, sodium chloride is table salt that you can eat Elements must combine in a specific ratio [based on mass] in order for the compound to form (water is always 1g Hydrogen to 8g Oxygen)

Solutions Solution – a mixture that looks like a pure substance where one substance is dissolved into another Solvent – the main substance of the mixture; has the most volume or mass Solute – the substance being dissolved; has the least volume or mass 100ml water + 10ml salt = saltwater solution (solvent) (solute) Soluble – can be dissolved in a particular substance Insoluble – can NOT be dissolved in that particular substance

Solutions Dissolve – a substance breaks down into smaller pieces and spreads out evenly within a different substance; the solute disappears and the solvent may change color Concentrated – compares similar solutions, has the MOST solute in it Diluted – compares similar solutions, has LESS solute in it Lemonade with 20g of sugar is concentrated compared to lemonade with 10g of sugar which is diluted

Solutions In a solution, the particles of the solvent are spread out and the solute particles fit in the empty spaces between Unsaturated – means there is still empty space that can be filled with more solute particles Saturated – means all the empty space is filled up and no more solute can be dissolved NOTE: If the temperature increases, the particles will spread out which can make more room. This means that something that was SATURATED can become UNSATURATED by adding heat.

Solutions, Suspensions, Colloids MIXTURECHARACTERISTICSEXAMPLES SolutionHomogeneous mixture (looks like one substance) Extremely small particles Evenly mixed Cannot be filtered out Will NOT scatter light (you can see through it) Occurs in Solids, Liquids, and Gases Salt water Kool-Aid ColloidParticles evenly spread out Particles large enough to scatter light (cannot see through it clearly) Particles too small to settle at the bottom Particles larger than in a solution Cannot be filtered out Jello Fog Milk SuspensionLarge visible particles Can be filtered out Heterogeneous mixture (can see different substances) Particles eventually settle to the bottom Scatters or blocks light (Not see-through) Snow globe Smog Italian dressing

Saturation Point The Saturation Point is the maximum amount of solute that can be dissolved at that temperature It is expressed as a UNIT RATIO 1.2g/ml 0.9ml/ml 0.123g/g Calculate the Saturation Point by dividing the solute by the solvent 12g salt/250ml water  0.048g/ml

Saturation Point when it just can’t hold any more

Dissolving Rates Different substances dissolve at different speeds. The faster a substance dissolves, the farther up the paper it will go Slower dissolving substances get left behind at the bottom or move up slowly We can identify a substance by its rate of dissolving – how far up the paper it moves in a certain amount of time