Science Final Exam Notes PDF

## Scientific inquiry - What is the pattern: does it increase, decrease, etc. - Evaluating hypothesis: correct or incorrect, etc. - Evaluating method: strengths and weaknesses (2) - Improvements and wishes ## Matter Is anything that takes up space and has a mass ## Atom An atom is the smallest pa...

## Scientific inquiry - What is the pattern: does it increase, decrease, etc. - Evaluating hypothesis: correct or incorrect, etc. - Evaluating method: strengths and weaknesses (2) - Improvements and wishes ## Matter Is anything that takes up space and has a mass ## Atom An atom is the smallest part of an element that has the properties of that element ## Parts of an atom - **Nucleus**: the center of the atom where neutrons and protons are located - **Protons**: protons are particles with positive charges which is inside the nucleus - **Neutron**: neutrons are particles that has no charge which is inside the nucleus - **Electron**: electrons are particles with negative charges which is located on the orbitals around the nucleus ## How to calculate number of e, p and n - **Atomic number** = number of protons - **Atomic number** = number of electrons - (number of protons = number of electrons) **Atomic mass**: number of protons + number of neutrons (The mass of the atom is concentrated in the nucleus) ## Substance - **A matter with a composition that's is always the same** - **Compounds**: a substance that is made up of more than one type of atom (can be solids, liquids or gases) (like H2O) - **Elements**: a substance that is made up of one type of atom only (like H) ## Property Characteristics that are used to describe something ## Physical properties Characteristics of matter that you can observe or measure without changing the identity of a Matter ## Mass Mass is a quantitative property (something I can measure) Is often measured in kilograms or grams ## Balance **Types:** - Double pan balance (2 pans) - Triple beam balance (3 beams) - Digital balance (scale) ## Weight The pull of gravity on the matter (n) Weight changes with location, but mass does not. Your weight will change on the moon than on earth. ## Size dependent Something that depends on the size of the sample. **Example:** Mass, weight, volume ## Size Independent Something that does not depend on the size of the sample. **Example:** Density, color, melting/boiling point, solubility, conductivity, magnetism ## Size dependant - **Mass**: the amount of matter in an object - **Weight**: the pull of gravity on the matter (weight changes with location, but mass does not) **Example**: If mass is 120 kg Weight will be: 120 kg x 10 = 1200 - **Volume**: the amount of space a substance takes up **Units: cm3, L, ml** ## Size independent - **Density**: the amount of mass per unit volume - **Color**: no matter the size the color will always be the same - **Melting / boiling point**: the temperature at which the material changes state - **Conductivity**: the ability of matter to let electricity pass through it - **Solubility**: the ability of one substance to dissolve in another - **Magnetism**: attractive force for some metals especially iron. - **Viscosity**: the measure of the liquids resistance to flow - **Honey**: has a high viscosity - **Water**: has a low viscosity - **Vapor**: gas state of a substance that is normally solid or liquid at room temperature - **Surface tension**: uneven forces acting on the particles at the surface of a liquid ## Volume After adding the object in the graduated cylinder with water we find the volume by: 40: the original amount of water - 60: the amount after adding the object = volume **Density** = mass (grams) ÷ volume (ml) If you change the liquid into foam the mass will stay the same however, the volume will change because the foam takes up more space than the liquid does. ## The process of splitting water A process by which hydrogen fuel is produced when water is broken down into oxygen and hydrogen. ## What make a state of matter? - Particle arrangement - Energy of particles - Distance between particles ## Kinetic theory of matter Matter is made up of particles which are in continual random motion. ## Solid - **Particles of solids are tightly packed** - **Vibrating about a fix position** - **Definite shape and definite volume** ## Liquid Articles of liquid are tightly packs but are far enough apart to slide over one another. - **Indefinite shape and definite volume** ## Gas Particles of gases are very far apart and freely. - **Indefinite shape and indefinite volume** ## Plasma - **Plasma is an ionized gas** - **Plasma is a very good conductor of electricity and its affected by magnetic field** - **Plasmas like gases have an indefinite shape and an indefinite volume** - **Plasma is the common state of matter** - **Some plasmas are found in flames, lightning, the northern lights** - **And the sun is an example of a star and its plasma state** ## Physical change Physical change is to change one or more physical properties in which the matters identity stays the same. **Some examples are water turning into ice cutting paper and folding clothes.** ## What is involved to getting matter to change state? Transferring energy to or from a substance can change its state. - **A form of energy is thermal energy** - **Thermal energy means heat** - **Turning solid into liquid is melting** - **Turning liquid into gas is evaporation** - **Turning liquid into solids is freezing** - **Turning gas into liquid is condensation** - **As well as changing from solid to gas is sublimation** ## What happens through the particles in the ice cube to cause a change in state? Melting matter can change state when it gains or loses enough thermal energy when the temperature of a substance increases the particles speed up when particle speed up they break away from other particle, this is the melting point of a substance. ## LESSON 1 Physical change: **What is physical change:** physical change is to change one or more physical properties in which the matters identity stays the same. **Some examples on physical changes are:** 1. Breaking glass 2. Mixing candies 3. Shredding paper 4. Folding paper 5. Melting ice **Question and answer:** 1. Decide which of the following is not a physical change. **Answer:** - Water turns into ice ✓ - Baking cake x - Frying an egg ✓ - Burning a match x ## 2. What is involved to getting matter to change state. - **Transferring energy to or from a substance can change its state** - **A form of energy is thermal energy** - **What does thermal mean?**: it means heat ## 3. How can state a matter be changed - From solid to liquid: melting - From liquid to gas: evaporation - From liquid to solid: freezing - From gas to liquid: condensation - Any change from solid to gas is sublimation ## 4. Does the number of particles change during a change of state? No only their spacing and arrangement changes. ## 5. Does the total mass of the matter change during a change of state? The total mass has not changed. ## 6. What happens to the particles in the ice cube to cause a change in state? Melting matter can change state when it gains or loses enough thermal energy when the temperature of a substance increases the particles speed up when particular speed of the break away from other particles this is the melting point of a substance. ## Key words - **The melting point**: the temperature at which the solid state changes to liquid state - **Vaporization**: the change in state from a liquid to a gas is vaporization/vaporization that occurs throughout a liquid is called boiling - **The boiling point**: the temperature needed for a substance to boil - **TIP**: a substances temperature will remain at its boiling point until all of the particles have changed from liquid to gas. - **Evaporation**: is vaporization that occurs only at the surface of a liquid - **Pressure and evaporation**: particles need to overcome the attractive forces between them aswell as overcome the force of air pressure and for particles to evaporate it must overcome the force of air pressure - **Freezing**: (the opposite of melting) the change of state from a liquid to gas - **The freezing point**: the temperature at which a liquid changes to a solid / freezing requires the removal of thermal energy - **As energy is removed from liquid particles is slow down and have less energy to overcome the chapter force is between particles and what start form an organised structure** - **Condensation**: the removal of thermal energy from a gas and a liquid is formed. - **TIP**: condensation is similar to freezing, as energy is removed the particles in the gas moves slower and cannot overcome the attractions between each particle and the liquid condenses ## LESSON 2: Chemical change: - **Chemical change**: a change in matter in which the substance changes into new substances with new chemical physical properties (was in the formative) ## What are the signs of chemical change? - Change in color - Change in odor - Warming or cooling - Formation of bubbles - Formation of precipitate - Release of light (was technically in the formative) ## What is a chemical reaction? It is a process that produces one or more substances that are different from the original substances. ## Types: - **Product**: any new substance formed during a chemical reaction - **Reactant**: substances that are present before the chemical reaction ## What is a chemical property? A characteristic that can be observed when the matter changes into a different type of matter. **QUESTION AND ANSWER:** 1. - **Physical properties of ash**: white powder - **Chemical properties of ash**: doesn't react with oxygen - **Physical properties of wood**: hard brownish solid - **Chemical properties of wood**: reacts with oxygen ## Chemical properties/ chemical reaction / chemical change 1. It is a process that produces one or more substances that are different from the original substances substances (chemical reaction) 2. Describe a substance if it's reacts with other substances or not (chemical property) 3. Exchange that produces new materials with new properties (chemical change) ## LESSON 3 Mixtures - **A mixture is:** a matter that can vary in composition ## Types - **Heterogenous**: a type of mixture in which the substances are not evenly mixed (fruit salad) - **Homogenous**: a type of mixture in which the individual substances are evenly mixed (tea with sugar) ## Separating Mixtures 1. **Mechanical separation**: often using hands 2. **Filtration**: a screen or paper that lets the liquid particles through but traps is solid particles. 3. **Evaporation**: vaporizing a liquid and leaving the dissolved solid behind us the separates salt solutions. 4. **Magnetism**: magnetic separation 5. **Separation funnel**: is a piece of laboratory glassware used in liquid-liquid extractions to separate the components. - **Distilation**: the separation of a mixture of liquid based on the physical property of boiling point ## ECOLOGY: - **LESSON 4 interactions within an ecosystem** - **Symbiosis**: is a closed long term relationship between two species that usually involves an exchange of food or energy ## Symbiotic - **Symbiotic**: relationships occur when two organisms live indirect contact and form a relationship. ## What are the different types of symbiotic relationships? **TYPES:** - **commensalism**: a symbiotic relationship that benefits one species but does not harm or benefit the other. - **Parasitism**: a Symbiotic relationship that benefits one species and harms the other. - **The species that benefits is the parasite** - **The species that is harmed is the host** - **Mutualism**: a symbiotic relationship in which both partners benefit ## What other types of relationships exist in ecosystems (not a symbiotic relationship)? - **Cooperative relationships**: cooperative relationships can be found in many different populations across the world. - **Predator - prey relationships**: is one in which one organisms, the Predator eats another the prey. ## Can this relationship be positive? Predators help prevent prey populations from growing too large for the carrying capacity of the ecosystems and keep the prey population healthy. - **Competitive relationships**: interactions between 2 or more organisms that need the same resource at the same time. ## LESSON 5: resources in an ecosystem - **Biotic factors**: living things - Animals - People - Plants - **Abiotic factors**: non-living things - Sun - Water - Soil - Rocks ## What is an ecosystem? All the living and nonliving things and how they interact in a given area make up an ecosystem. **TIP:** All of the ecosystems on earth make up the biosphere. **Biosphere**: is the parts of earth and the surrounding atmosphe where there is life ## Populations - **Populations**: is all the organisms of the same species that live in the same area at the same time. - **Species**: is a group of organisms that have similar traits and are able to produce fertile offspring - **Community**: is all the populations of different species that live together in the same area at the same time. ## What is the difference between and Ecosystem and a community? - **An ecosystem** is All the living and nonliving things and how they interact in a given area make up an ecosystem. - **A community** is all the populations of different species that live together in the same area at the same time. ## Limiting factor: - **Limiting factor**: is anything that restricts the size of a population. ## TIP: - Populations can increase and decrease in size but limiting factors might affects the number of individuals an Ecosystem can support. ## EXAMPLE: - Water - Food - Sunlight - Temperature - Space/shelter ## Biotic potential: - **Biotic potential**: is the potential growth of a population if it could grow in perfect conditions with no limiting factors. ## Carrying capacity: - **Carrying capacity**: is the largest number of individuals of one species that an ecosystem can support overtime. ## Overpopulation: - **Overpopulation**: when a population size grow so large that its causes damaged to the environment. ## QUESTION AND ANSWER: ## What are the problems that can be caused by overpopulation? - Population of birds eats spiders an Overpopulation of birds causes the size of the spider population in that community to decrease, populations of other animals that eat spiders also decrease when the number of spiders decreases. ## Population size can increase but it also can decrease for example 1. Population of field mice my decrease in size in the winter because there is less food. 2. Natural disaster such as flood fire volcanic eruptions also affect population size. 3. Sometimes a populations size can decrease to such an extent that it may threaten the entire species. ## LESSON 6 CHANGING ECOSYSTEMS - **An ecosystem** can change over time change usually happen so gradually that you might not notice the differences from day to day. ## Ecological Succession: - **Ecological succession**: is the process of one ecological community gradually changing into another. - **Ecological succession** occurs in a series of steps for example small plants usually grow first water plant such as trees usually grow last. - **Climax community**: a stable community that no longer goes through major ecological changes. ## Types: 1. **Primary succession** - **Ecological succession** in new areas of land with little or no soil vegetation like lava flow, sand dunes and exposed rocks. 2. **Secondary succession** - **Ecological succession** in areas where existing ecosystems have been disturbed or destroyed like forest land cleared hundreds of years ago gradually grew back to a Climax community of beech and maple trees. - **Aquatic succession**: fresh water ecosystems change over time in a natural and predictable process this process is aquatic succession. - **Sediments**: any material that broken down by the process of weathering and then transported by wind water or Gravity. - **Runoff** can move sediment into streams and other water passages. - **Too much Sediment** can damage stream habitats, clog waterways and cause flooding. - **Negative environment impacts** of Sedimentation includes habitat loss. - **Change in available nutrients** and coastline alteration. - **Sediment** that is suspended in water may reduce visibility and make it difficult for animals to find food. - **It may also prevent light** from reaching plants that needs and sunlight for food. - **Sediment** that has collected on the bottom of rivers and streams may cover habits of fish or other animals. - **The ecosystem** operates under dynamic equilibrium which describe the balance between different parts of the ecosystem. - **The change in environment** can last for years after such a change happens with balance is lost and individual organisms of a species might not be able to find the resources they need to survive. - **Effects of change** from natural disruptions such as forest fires, floods, volcanic eruptions and disease can cause massive amounts of damage ecosystem. - **These sudden changes** may make it difficult for organisms to adapt. - **Some disruptions** like mountain formation may not happen suddenly but over many years. - **In some cases** these changes have benefits such as control the size of population or allowed net growth of plant life.