Science Exam Review PDF

Astronomy (Seasons:) The tilt of Earth’s axis creates seasons as Earth moves around the Sun (tilted 23.5 degrees) -​ Tilt and revolution result in seasons and daylight hours changing throughout the year -​ When the Northern Hemisphere is tilted towards the sun, it is summer in the...

Astronomy (Seasons:) The tilt of Earth’s axis creates seasons as Earth moves around the Sun (tilted 23.5 degrees) -​ Tilt and revolution result in seasons and daylight hours changing throughout the year -​ When the Northern Hemisphere is tilted towards the sun, it is summer in the Northern Hemisphere and winter in the Southern Hemisphere (vice-versa) (Planets:) -​ Planets stay in their orbit due to their velocity and gravity of the sun -​ Greater Mass = Greater gravitational pull Inner Planets: Mercury, Venus, Earth, Mars -​ Known as terrestrial planets, largely made of rock and composed like Earth Outer Planets: Jupiter, Saturn, Uranus, Neptune -​ Known as Gas Giants as they are very large and made mainly of gas -​ Have rings made up of rock and ice that orbit around the planet Dwarf Planets: Pluto, Ceres, Haumea, Makemake, Eris -​ Not officially recognized as planets as they do not meet all of the criteria -​ Large enough they get pulled into spherical shape by gravity (yes) -​ Orbit a star (yes) -​ Large enough gravity has cleared all objects from their orbit (no) (Distances In Space) Astronomical Unit (AU): Used to measure distances in our solar systems -​ Distance between Earth and Sun is 1 AU -​ 1 AU = 149,000,000 km Light Year (ly): Used to measure distances in interstellar space, outside our solar system -​ Distance light travels in one year -​ Nothing in our universe can move faster than light -​ 1 ly = 9.461 x 10^12 km (Scientific Notation)  -​ Method used to express very large numbers -​ Coefficient is always a number bigger than or equal to 1 and less than 10 -​ Base of 10 raised to an integer exponent How to multiply Scientific Notation? 1.​ Multiply the Coefficients (5x10^3) 2.​ Add the powers 3.​ Rewrite answer in correct scientific notation 5x10^3 x 4x10^2 = 20 x 10^3+2 = 20 x 10^5 =2 x 10^6 (move one decimal to left because coefficient has to be below 10) How to divide Scientific Notation? 1.​ Divide the coefficients 2.​ Subtract the powers 3.​ Rewrite correct scientific notation 20x10^4 / 4 x 10^2 = 5 x 10^4-2 =5 x 10^2 (Unit Conversions) Dimensional Analysis (DA): Method used to convert between units 1.​ Multiply given info by the necessary conversion factor (cross unit out) 2.​ Put unit you are trying to find on the top 1 m = 100 cm 1 km = 1000 m 149,000,000 km = 1 AU 1 ly = 9.461 x 10^12 km Example: Convert 2.5 million ly to km Conversion factor: 1 ly = 9.461 x 10^12 km 2.5 x 10^6 ly (cross ly out) x 9.461 x 10^12 km/ 1 ly (cross ly out) = 2.5 x 9.461 x 10^18 = 23.65 x 10^18 = 2.36525 x 10^19 (For 2 part calculations, do them in succession) Satellites:  -​ Any object that orbits around a planet -​ Moons are natural satellites -​ Artificial satellites are set into orbit by humans and have uses such as internet, cell phones, TV, etc Asteroids: -​ Between Mars and Jupiter, there are thousands of smaller objects known as asteroids -​ This area is known as the asteroid belt -​ Small rocky objects that orbits around the Sun -​ No large object likely to collide with Earth in next several hundred years Comets: -​ Revolve around Sun in fixed orbits -​ Different from meteors and asteroids as it is mostly made of ice and dust, and looks like it has a long tail -​ Front Part = Nucleus (usually a few km wide, resembles big dirty snowball) Meteoroids: -​ Small rocky object moving through space -​ Much smaller than asteroids Meteors: -​ Meteoroid that has entered Earth’s atmosphere, burns up and creates bright streak in the sky -​ (Not Shooting Stars) Meteorites: -​ Meteor that doesn’t burn up completely, and lands on Earth’s surface -​ Can cause damage to the planet if large enough (Moon): -​ Takes 27.3 days to orbit Earth, also takes 27.3 days to rotate on its axis (therefore, we always see the same side of the moon) -​ We never see the “dark side of the moon” -​ Non-Luminous -​ Appears to shine, as sunlight is reflected from its surface -​ No atmosphere -​ ⅙ of Earth’s gravitational field (Moon) cont.:  -​ Moon’s orbit is 5° tilted Phases of the Moon: 1.​ New Moon 2.​ Waxing Crescent 3.​ First Quarter 4.​ Waxing Gibbous 5.​ Full Moon 6.​ Waning Gibbous 7.​ Third Quarter 8.​ Waning Crescent Crescent: Any time less than half the moon is lit Gibbous: Any time more than half the moon is lit Solar Eclipse: Moon is directly between Sun and the Earth Lunar Eclipse: Earth is directly between Sun and the Moon Planetary Transits: When a planet moves between Earth and the Sun (Stars): -​ Hot ball of electrically charged gas -​ All stars are luminous (nuclear fusion in their core) -​ Largely comprised of hydrogen gas which fuses to form helium Luminosity: Amount of energy star produces per second -​ Sun = 1 (Star with luminosity of 1 is 100x brighter than the sun) Apparent Brightness: How bright a star looks to us from Earth Colour and Temperature: Red star = relatively cool (3000°) Yellow star = relatively hot (6000°) White star = even hotter (10,000 °) Blue star = very hot (20,000° - 50,000°) Sun (our star): -​ Hot ball of plasma  -​ Has 99.8% of all mass in our solar system -​ Its gravitational pull keeps Earth in orbit -​ Composed of 92.1% hydrogen, 7.8% helium, 0.1% other elements Sun’s Structure: Interior: Core: Reaction centre of the Sun Radiative Zone: Surrounds the core Convective Zone: Surrounds radiative zone Atmosphere: Photosphere: Boundary between inside and outside of the Sun Chromosphere: Thin layer outside photosphere Corona: Outermost layer of the Sun Solar Wind: Extreme heat on surface of the Sun that causes solar wind Sun Spots: Earth sized cooler areas on the Sun Solar Flare: Massive eruption on the surface of the Sun - suddenly throwing plasma and magnetic energy BIG BANG THEORY: -​ All matter compacted into little hot, dense ball under extreme pressure, EXPLODED, hurling matter and energy into all directions -​ (BEGINNING OF TIME) Problems with this theory -​ Assumes nothing becomes everything -​ Does not follow laws of nature -​ Just a theory NEBULA THEORY: -​ Enormous cloud of dust and gas formed the solar system -​ Sun like all stars is formed from Nebula -​ Nebula contracts and spins (gravity), flattens into a pancake bulge, which became the Sun -​ Cooler material who clumped together (gravity) became planets Greenhouse Effect: -​ Earth absorbs 50% of the sun’s energy -​ Earth and water release this energy as heat _____________ Universe: -​ All forms of matter and energy, everything that physically exists -​ Made up of galaxies Galaxies: -​ Extremely large area of space -​ Contains hundreds of billions of stars, and planets and dust -​ Held together by gravity -​ Galaxies that have a lot of dust, can produce new stars -​ Ancient galaxies have basically zero dust, as it was all used up to produce stars -​ Also contains star clusters, close knit group of stars What is our Galaxy? -​ The Milky Way -​ Contains 400 billion stars -​ Gravity from Black Hole holds our galaxy together What is the closest galaxy to us? -​ Andromeda (2.5 billion ly from Milky Way) How do we know the Universe is constantly expanding? (RED SHIFT): -​ As the galaxy moves away, the wavelength of light gets longer and shifts to the red part of the spectrum. Theories on how the Universe ends 1.​ Universe will expand for an infinite time 2.​ Universe will hit a brick wall, and everything will destroys everything that once was 3.​ Universe will reach steady-state, not growing or shrinking BLACK HOLE: -​ Area at center of a galaxy where gravity is so strong, that nothing can escape -​ Is so strong it can pull stars into it, adding even more mass and gravity to the black hole Biology Food Web o Trophic levels ​ 1st Level: Producers that make their own food (plants and algae) ​ 2nd Level: Primary consumers that eat producers (ex. herbivores) ​ 3rd Level: Secondary consumers that eat primary consumers (ex. carnivores) ​ 4th Level: Tertiary consumers that eat secondary consumers such as carnivores ​ Apex Predators: Organisms that do not get eaten by any other organism in the community (Highest Level) o Producer vs consumer ​ Producers make their own food while consumers get their energy by eating it. (Producers produce something while consumers consume it) o Herbivore, omnivore, carnivore, decomposer ​ Herbivores: Eat only plants, such as flowers, grass, and nuts. -​ Ex. rabbits, deer, and grasshoppers. ​ Omnivores: Eat both plants and animals, such as humans, bears, raccoons, and pigs. -​ Omnivores have teeth that are similar to carnivores, which helps them tear meat, and flat molars for grinding food. ​ Carnivores: Eat only other animals, such as foxes, hawks, and lions. -​ Carnivores have adaptations that help them catch their prey. ​ Decomposers: Eat dead or decaying organisms, such as earthworms, bacteria, and fungi. -​ Decomposers break down dead organisms and return nutrients to the soil. o How a change in the web affects other species Changes in a food web can have complex effects on other species, even species that aren't directly connected. These changes can ripple through the ecosystem, affecting organisms at multiple levels. Nutrient Cycles o Carbon Cycle o Nitrogen Cycle ​ Nitrogen Fixation: Lightning and bacteria convert nitrogen gas into ammonia, which plants can use. ​ Nitrification: Specialized bacteria convert ammonia into nitrites and nitrates. ​ Assimilation: Plants use nitrogen compounds to build proteins and other organic compounds. Animals eat plants and convert the plant proteins into animal proteins. ​ Ammonification: the process of converting organic nitrogen compounds into ammonia. ​ Denitrification: the process of converting nitrogen compounds into nitrogen gas and nitrogen oxides. Why is the Nitrogen cycle important? -​ Used to make DNA/ RNA -​ Used to make ATP -​ Used to make proteins Nitrogen makes up around 78% of the atmosphere in the form of Nitrogen gas (N2) o Water Cycle ​ Evaporation - The sun heats water surfaces and turns it to gas (water vapor) ​ Transpiration – Plants release water vapor from leaves into atmosphere ​ Condensation – vapor gathers and forms clouds ​ Precipitation – Water then falls from the ​ clouds (rain, snow, hail etc) ​ Seepage – some water seeps into the ground and finds itself in aquifers (taken up by roots of plants) ​ Aquifers = underground lakes ​ Runoff – water “bleeds” off back into stream water bodies Photosynthesis and Cellular Respiration o Define each process and how they are related Photosynthesis and cellular respiration are biological processes that convert energy and matter in living organisms and the environment. PhotoSynthesis: -​ Plants use sunlight, water, and carbon dioxide to create oxygen and glucose -​ Glucose is used as food by the plant -​ Takes place in chloroplasts, which are small structures in plant cells Cellular Respiration: -​ Cells use oxygen, water, and glucose to create carbon dioxide, water, and ATP (energy) -​ ATP is used to fuel growth and other cellular functions -​ Takes place in cells with mitochondria Relationship: -​ Photosynthesis and cellular respiration are essentially the reverse of each other -​ They work together to maintain the balance of oxygen and carbon dioxide in the atmosphere -​ Both processes involve the exchange of gases and the production of energy o Word/Chemical Equation Photosynthesis: carbon dioxide + water + light energy → glucose + oxygen 6CO2 + 6H2O → C6H12O6 + 6O2 Cellular Respiration: glucose + oxygen → carbon dioxide + water + Chemical Energy (in ATP) C6H12O6 + 6O2 → 6CO2 + 6H2O Human Activities and their impact on ecosystems o Pollution Pollution can have harmful effects on ecosystems by damaging habitats, reducing biodiversity, and harming wildlife.They can poison organisms and cause rapid and harmful changes in the environment. These changes may stress certain species, making them more vulnerable to disease and seasonal conditions like drought and cold, and may reduce their ability to respond and survive. o Plastics Plastic pollution has a significant impact on ecosystems, including the marine environment, soil, and air. Plastic pollution can harm animals, alter habitats, and contribute to climate change o Habitat Loss Habitat loss can significantly impact ecosystems by reducing biodiversity, fragmenting ecosystems, and causing species to become extinct. Habitat loss can fragment ecosystems and can cause species extinctions, while habitat restoration can increase local biodiversity and species populations. The evolution of life cycles and traits that help species survive and reproduce in disturbed or altered ecosystems. Ecological Pyramids o Energy The pyramid of energy is the ecological pyramid constructed by measuring the flow of energy from a particular trophic level to the next. -​ The ecological pyramid of energy is always erect/inverted. -​ The producers at the bottom of the energy pyramid have the most energy, while the uppermost consumer at the top has the least energy. -​ The energy content of every level of trophic structure in an ecological system is addressed by this pyramid. -​ The standard energy pyramid is divided into three levels: producer, consumer, and decomposer. -​ The producers, at the bottom of the pyramid, have the greatest energy from the sun fixed via photosynthesis. -​ creatures at the consumer level take in the plants at the production level. -​ The decomposer level is at the top of the pyramid and contains creatures that break down dead stuff. -​ The flow of energy within this pyramid demonstrates that energy cannot be generated or destroyed, as stated by the law of thermodynamics. -​ Lindeman’s 10% rule – According to Lindeman’s 10% regulation law, only 10% of the energy is transported from one level to another since nearly 90% is lost as heat energy is used in breathing, some are used in physiological cycles, and the remainder is consumed by decomposers. o Biomass The biomass pyramid is a pyramid that shows the total mass/ weight of each trophic level in a certain food chain in an ecosystem. -​ The ecological pyramid of biomass, like the pyramid of numbers, can be upright or inverted. -​ The biomass pyramid represents the ecological pyramid formed by taking into account the amount of biomass generated by each trophic level’s living system. -​ Producers have the most biomass in this pyramid, followed by primary consumers, who have a smaller amount of biomass than producers. -​ As the number of producers increases, forest and grassland ecological systems are examples of upright biomass pyramids. -​ Because a vast number of zooplankton rely on a smaller amount of phytoplankton, the ocean ecosystem is an example of an inverted pyramid. -​ Secondary consumers possess less biomass than the primary consumers, and biomass is found at the peak of the pyramid. -​ Depending on the trophic level of an ecosystem, approximately 15 to 20% of biomass is transferred to the next level o Numbers Ecological Pyramid of Numbers The number of creatures in each trophic level constitutes a level in a pyramid of numbers. -​ Ecological Pyramid of Number represents the number of organisms in each trophic level without taking into account their individual sizes or biomass. -​ The number pyramid is normally upright. -​ However, in other cases, the pyramid is not erect. For example, in the detritus food chain, several creatures feed on a single dead plant or animal. -​ As one travels up the pyramid, the number of creatures diminishes. -​ It’s near the bottom since there are so many producers Chemistry GRASS G – Given (what info is given in the question) R – Required (what are you trying to find) A – Analysis (What formula are you going to use) S – Solution (show your work) S – Statement (sentence that explains solution ​ Matter is defined as anything that occupies space has mass. ​ Mass is how much matter is in an object ​ Volume is how much space the substance occupies ​ Matter can exist as a solid, liquid, or gas 1.​ All matter is made of very tiny pieces called particles (atoms) 2.​ All particles have spaces between them. (solids closely packed ordered, liquids not as closely packed disordered, gases very far apart in random manner) 3.​ The particles are always in constant motion. (In solids, the particles vibrate in position,  In liquids, the particles slide and roll past one another in random motion. In gases, the particles move freely at high speeds and in random motion.) 4.​ The particles in a substance attract each other 5.​ The amount of attraction is different for different states of matter: SOLIDS: Very Strong LIQUIDS: Strong GASES: Weak 6.​ As temperature increases, particles of matter move faster & viscera Matter can be divided into 2 general categories Pure substances A substance that is made up of only one type of Particle, Example pure distilled water only H20 Elements & Compounds Elements A substance that is made up of only one type of Atom Ex: Gold, silver, aluminum, hydrogen etc –– Compounds A substance that is made up 2 or more atoms or elements Ex: Water (H2O) or Salt (NaCl) Mixtures A substance that is made up of at least 2 different types of particles Or in other words, made up of 2 or more pure substances ​ Example: salt water Mechanical & Solution Mixtures Mechanical Mixture/Heterogeneous A mixture in which you can see the different types of matter. Ex. chocolate chip cookie Solution/Homogeneous A uniform mixture of two or more substances Ex. salt water. Alloy A solid mixture of 2 or more metals Physical & Chemical Properties of Matter ​ A physical property is a characteristic or description of a substance that can be used to identify it ​ State (at room temperature): solid, liquid or gas ​ Colour: matter can also be colourless ​ Texture: fine, coarse, gritty… ​ Odor: burnt, fruity, flowery, odourless ​ Luster: objects with luster reflect light and look shiny. The opposite is dull. ​ Clarity: Describes whether light passes through the object: Transparent = All light passes through. Looks clear. Translucent = Some light passes through. Looks cloudy. Opaque = No light passes through. Can’t see through it. ​ Taste: sweet, sour, salty, bitter ​ Viscosity: how easily a LIQUID pours or flows Ex. Water is not viscous, honey is viscous ​ Malleability: if a material can bend without breaking The opposite is brittle. ​ Ductility: If a material can be stretched into a wire.  ​ Conductivity: if heat or electricity can pass through it. The opposite of a conductor is an insulator. ​ Magnetism: If it will stick to a magnet. ​ Freezing point & boiling point ​ Solubility: Materials that are soluble dissolve (mix easily) in water. The opposite is insoluble. ​ Hardness: Describes how easily a material can be scratched. ​ Density: Describes how much mass per volume a material has ​ Qualitative: Physical Properties can be observed without measurement. You Can observe them using your senses. ​ Quantitative: Physical Properties are described using numbers and units of measurement Chemical Properties ​ A chemical property describes how a substance behaves when it reacts chemically with another substance ​ We cannot observe chemical properties using our senses (like we can with physical properties) ​ Chemical properties are revealed when the material goes through a chemical reaction ​ Combustibility/Flammability: Some materials can be burned if exposed to a flame, spark or heat. (Oxygen must be present!) ​ Materials have different abilities to burn, and some don't burn ​ Reactivity with water: Ex. some materials bubble or burn in water ​ Reactivity with oxygen: Ex. Rusting is a reaction between a metal and oxygen in the air ​ Reactivity with acid: Ex. Baking soda reacts with vinegar (acetic acid) ​ Reactivity with Light: Ex. photosynthesis Physical Changes ​ Ice Melting to form water. Ice and water are the same substance just in different physical states. We can freeze water to get the ice back, all changes of state is a physical change  ​ Ripping Paper – The change cannot be easily reversed...but no new substance has been created. The paper is still paper. – Anytime something changes its form it is a physical change Chemical Changes ​ During a chemical change the original substance changes into one or more new substances that have different properties. ​ Most chemical changes are difficult to reverse ​ Baking a cake – Anytime something is cooked or burned, a chemical change takes place. We cannot get the uncooked substance back. Clues that a Chemical Change Has Happened ​ A new colour appears ​ Light or heat is given off ​ Bubbles of gas are formed ​ A solid material known as a precipitate forms in a liquid. ​ The change is difficult or impossible to reverse Elements v.s. Compounds ​ Element A pure substance that cannot be broken down into simpler substances ​ Compound A pure substance composed of two or more different elements ​ Silver (Ag) ​ Tin (Sn) ​ Mercury (Hg) ​ Tungsten (W) ​ Potassium (K) ​ Sodium (Na) ​ Lead (Pb) ​ Gold (Au)  ​ Iron (Fe) ​ Antimony (Sb) ​ Group 8 – Noble Gases (colourless, gas at room temp., very unreactive) ​ Group 7 – Halogens (Most reactive of non-metals) ​ Group 2 – Alkaline Earth Metals (Second most reactive elements on table) ​ Group 1 – Alkaline Metals (All shiny, metallic metals) ​ Metalloids (mix of both metal and non-metal properties) ​ Non-Metals ​ Transition Metals ​ Each horizontal row is called a period on the periodic table Ions An atom with a charge. Positive or negative. Ionic Bonds: 1.​ Always formed with a metal and nonmetal 2.​ Metals always lose electrons 3.​ Gives away electrons 4.​ Cations= + charged ion 5.​ Anions = - charged ions 6.​ Naming: Metal name + Non metal name ending in ide Ex: NaCl sodium chloride 7.​ Formula: Cross the charges for example Covalent Bonds: Sharing electrons Two non metals Examples N2o5= Dinitrogen Pentoxide Numbers come from the amount of each atom needed 1= Mono 2= Di 3- Tri 4= tetra 5=penta 6= hexa 7=hepta 8= octa 9= Nona 10= Deca