click below
click below
Normal Size Small Size show me how
Grade 9 Science Exam
Grade 9 Science Review
Question | Answer |
---|---|
What is matter? | Matter is anything that takes up space and has mass. |
What is chemistry? | Chemistry is the study of matter. |
What is a physical change? | Physical change is when the appearance of a substance changes, but chemical structure stays the same. Reversible |
What is a chemical change? | New substance is formed with new chemical structure. Irreversible |
5 Indications of a chemical change has occurred | 1. New color 2. New gas is formed(possibly new odor) 3. Light is produced 4. Heat is lost or gained 5. Precipitate forms (2 liquids form a solid) |
What is a physical property? | a characteristic of a substance that may help you identify it. |
What is a chemical property? | The behavior of a substance as it becomes a new substances. |
what is the particle theory? | 1. all matter is made of particles 2. pure substance have their own particles 3. particles are always moving 4. there are attractive forces between particles. |
What is a pure substance? | Contains only 1 kind of particle. |
What is a element? | a pure substance that can not be broken down into simpler substances. |
What is a compound? | a pure substance that contains 2 or more different elements in a fixed proportion. |
What are molecules ? | when 2 or more atoms join together. |
What are mixtures? | contains 2 or more pure substances or 2 different types of particles. |
What is a homogeneous mixture? | A substance that is composed of similar elements(uniform nature) |
What is a heterogeneous mixture? | 2 or more substances are visible. |
What are electrons? | Negative charged subatomic particle. located around nucleus. 0 units |
What are Protons? | positive charged subatomic particle. Located in the nucleus. 1 unit |
What are neutrons? | Neutral subatomic particles. Located around the nucleus. 1 unit |
How many electrons are allowed as a maximum on each valence shell? | 2 8 8 2 |
What is the octet rule? | all atoms want to have a full valence shell.(8) |
2 types of bonds? | Covalent & Ionic |
What are ionic bonds? | nonmetal + metal |
What are covalent bonds? | nonmetal+ nonmetal |
What is electricity? | is based on electron flow |
What is electrostatics? | the study of electricity |
What is the electrostatic series? | a list of substances describing their relative attraction for electrons |
What are ions? | Charged atom which have gained or lost electrons. |
What are the 2 ways of charging an object? | Charge by contact charge by induction |
What is charging by induction? | near the object |
What is a conductor? | Materials that allows electrons to flow easily |
What is an insulator? | materials that hold electrons tightly and do not transfer electricity well. |
What is grounding? | ground wire is connected to the earth to dilute the earth |
What are 3 uses of static electricity? | 1. Pollution & dust control 2. coating surfaces 3. Copying printed material |
What are the four parts of a electric circuit? | 1. Switch 2. source 3. conducting wire 4. Electrical load |
What is the law of repulsion? | it is the law which like objects are repelled and opposites are attracted. |
What is electric current? | flow or movement of electric charge from one place to another. |
What is a source? | source of electrical energy |
what is an electrical conductor? | wire that provide a controlled path for the flow of electrical current |
What is an electrical load? | device that converts electrical energy into useful energy |
What is CURRENT? | rate at which a number of electrons move past a given point through a circuit in 1 second |
What is current measured in? | amperes |
What is an ammeter? | measures electrical current |
What is the formula for current? | I = Q/T |
I = | current (amperes/A) |
Q = | charge moving past a point(coulomb/c) |
T = | Time (seconds/s) |
What is an open switch? | no current flows |
What is a closed switch? | current flows |
What is voltage? | Electric Potential" potential given to each e- as it leaves a source |
What is a voltmeter? | it measures difference in potential energy on one side of the load and the other. |
What is potential difference? | Is how much energy a load (can) uses up |
What is voltage measured in? | Volts |
V = | Voltage (v = volts) |
E = | Energy (j = joules) |
Q = | charge moving past a point (c = coulomb) |
What is the formula for voltage? | V = E/Q |
What is resistance? | a property that inhibits electrical motion, converts electrical energy to other energy forms. (more resistance it is harder to push coulombs through wire) |
What is resistance measured in? | ohms |
What is the formula for resistance? | R = V/I |
What are the 4 factors that affect resistance(of a wire) | 1. Temperature- higher temp = greater resistance 2. Length - resistance increases with length 3. Cross sectional area - resistance decreases with a larger areas 4. Material - depends on the structure of the atoms of the metal |
What is power? | Describes the amount of electrical energy that is converted into heat, light, sound or motion in 1 second. |
What is power measured in? | Watts (W) |
What is the formula for power? | P = E/T |
What is the 1st law of thermodynamics? | energy is not created or destroyed, only changed to different forms of energy |
What is input energy? | amount of energy used to operate a system. |
What is output energy? | useful energy obtained from the systems |
What is waste energy? | energy that is not helpful. |
What is the formula for efficiency? | Energy output/Energy input X 100% |
What is a fuse? | a metal conductor that has a much lower melting point than conducting wires. - when melted, current stops flowing. - new fuse will beeded when fuse is blown. |
What is a circuit breaker? | - bimetallic strip bends with hot wires, releasing a hook to stop current flow - reset hook to start circuit again |
What is a hot wire? | carry electrical energy (red/black) Large devices get 2 hot wire small devices get 1 hot wire |
What is a ground wire? | - one wire entering the is neutral - connected to all appliances. |
What does D.C. stand for? | Direct current. |
What does A.C. stand for? | Alternating current/. |
What is direct current? | Electrons travel continuously in 1 direction. |
What is alternating current? | electrons rapidly change direction back and forth. |
What is a primary cell? | - Disposable energy - when all material is discharged, all is used up |
What are 2 examples of a primary cell? | Wet cells/voltaic cells Dry cells- battery is a collection of dry batteries |
What is a secondary cell? | a battery that can regain its charge |
What is Ecology? | The study of how organisms interact with each others. |
What is an ecosystem? | term used to describe the relationships among species living in a environment and the relationship among those organisms and non-living components of the environment. |
What is an ecotone? | a transition area between 2 ecosystems/ecozones that contain species and characteristics of both ecosystems; therefore having greater biodiversity. |
What does abiotic mean? | non-living factors or influences on organisms such as amount of sunlight, temperature and strength or direction of wind. |
what does biotic mean? | Factors caused by the presence and roles of other living things |
What is population? | all of the members of the same species, living in the same ecosystem or habitats |
What is a habitat? | the conditions required for the survival of a particular species. |
What is a community? | the collection of all populations of all the species in a ecosystem or habitat is called the community of organisms |
What is a biome? | a collection of ecosystems that are similar or related to each other by a dominate form. |
What is a food chain | they show the predator-prey relationship |
What is a food web | are complex and show more inter-relationship. (they provide a more accurate picture of the ecosystem) |
What is the 2nd law of thermodynamics? | anytime energy is converted, some of the energy is converted into an unusable form usually thermal energy that can not be converted |
What is photosynthesis? | Sunlight is converted into sugar. (Stored chemical energy) |
What is cellular respiration? | Sugar is converted to useful chemical energy. |
What are food pyramids? | they show relationships between trophic levels. they are another wasy of showing food chains. |
What are the 3 types of food pyramids? | Numbers, Biomass & energy. (least to greatest) |
What is a species? | organisms that are similar and can mate to produce fertile offspring. |
What are the 4 ways a population can change sizes? | Births, Deaths, Immigration, Emigration. |
What is bioaccumulation? | pesticides that accumulate in the fatty tissue. |
What has a closed populations? | Populations that do not have immigration & emigration. |
What are the 4 layers of soil? (top to bottom) | Litter, topsoil, subsoil, bedrock |
What is population growth? | Births + immigration - emigration - deaths |
What is biotic potential? | the max # of offspring a species can produce.(depends on 4 factors) |
What are the 4 factors that affect biotic potential? | 1. Birth potential 2. Capacity for survival 3. Procreation 4. Length of reproductive life |
What is carrying capacity? | the max # of individuals that an ecosystem can support |
What is a critical number? | the # of organisms below which extinction will result for that species. |
What are 3 words used to describe soil? | Acidic, neutral, basic. |
What the 3 things that determine the pH of soil? | 1. The nature of the rock from which the soil was formed. 2. the type of plants that grow in it, die & decompose. 3. The rain & snow that falls on the soil. |
What are the 3 factors that determine the type of biome and will influence the type of plants? | 1. Temperature 2. Amount and type of precipitation 3. Latitude |
What is a celestial body? | an object in space that are visible from earth. (sun, moon stars, planets) |
What is a asterism? | a distinctive star pattern. (the big dipper) |
What is a constellation? | a group of stars that form a pattern. |
What is a planet? | a celestial body that orbits a star and does not produce its own light. |
What is a supernova? | a huge explosion constituting the death of a star. |
What is a nebula? | a vast cloud of gas & dust, which may be the birth place of a star. |
What is a black hole? | in space, an object having such strong gravity that nothing, not even light can escape it. |
What is a neutron star? | a small super dense star thought to be the crushed remnant of a large star that has exploded as a supernova. |
What is a white dwarf? | a small super hot star that is not very bright. |
What is a light year? | the distance that a beam of light travels in a vacuum in 1 year. (9.46 trillion km) |
What is the geocentric model? | The earth centered model; proposed by Aristotle. |
What is the heliocentric model? | The sun centered model; proposed by copernicus. |
What is day & night caused by? | the rotation on the earth's axis |
What does the tilt cause? | it causes differences in temperature, hence seasons. |
what degrees is the tilt at? | 23.5 degrees. |
What are the 2 types of rays? | Direct & slanting rays. |
What is an asteroid? | Irregular shaped bodies made of carbonaceous or silicate rock. (also called minor planets) |
What is a comet? | a celestial body made of ice & dust. (dirty snowballs) |
What is a meteor? | a shooting star made of dust & rock. |
What is a metorite? | A meteor that hits earth. |
What is a series circuit? | The electrons only have 1 path to follow and the all appliances share electrical pressure. |
What is a parallel circuit? | The electrons have more than 1 path to follow and the appliance do not share electrical pressure. |
What is a spectroscope? | a device that splits light into a pattern of colours. |
What is luminosity? | the amount of energy a star radiates per second. |
What are stars formed from? | giant clouds of gas and dust known as nebulae. |
What does starlight provide? | information about the star's brightness, color temperature, composition, mass & size. |
What is color used to find? | Temperature (smaller wave length = hotter star)& the composition of a star. |
RED = | cool |
YELLOW = | hot |
BLUE = | very hot |
What are the 3 types of galaxies? | Spiral, elliptical & irregular. |
What is a galaxy? | stars, gas & dust held together by gravity. (they occur in clusters like stars) |
What are the 2 types of clusters that stars are found in? | Open clusters & globular clusters. |
What is our galaxy? | The milky way. |
What is a spiral galaxy? | pinwheel shaped with arms of gas, dust & bright blue stars. (Which indicate the formation of new stars) |
What is type is our galaxy? | Spiral galaxy. |
What is an elliptical galaxy? | a football shaped of mostly old stars with little gas & dust. |
What is a irregular galaxy? | young & old stars in gas and dust. Usually small and less common. |
What are the 3 ways of transferring electrical charge? | By friction, by contact, and by induction. |
What are the 3 things involved in the nitrogen cycle? | Decomposer, bacteria and animals. |
What is nitrification? | The process in which atmosphere nitrogen converting to nitrates. |
What is dentification? | Process performed by some soil bacteria in which nitrates are converted to nitrates and then to nitrogen gas. |
What are the 2 processes involved in the carbon cycle? | Photosynthesis and cell respiration. |
What are tides caused by? | The gravitational pull of the moon. |
During a lunar eclipse what is in the centre? | The earth. |
During a solar eclipse what is in the centre? | The moon. |
When would the sun be above the horizon for the most hours? | June 22 the Equinox. |
In which season can we see the big dipper? | every season. |
What is the hubble? | a telescope. |
How do you figure out the number of neutrons? | Atomic mass - atomic number = number of neutrons |
What is an isotope? | An atom with different number of neutron and different atomic mass, but is the same element. |
What are the 4 main abiotic factors of ecosystems? | Light, temperature, wind and moisture. |
What are the 3 light factors in an ecosystems? | Intensity, duration and quality. |
What is an organic substance? | A substance always containing atoms of carbon and hydrogen. |
What is the definition of extirpated? | any species that no longer exists in a certain part a country. |