science test

• All matter is made of of tiny particles that have empty spaces betweem them
• Different solutions are made out of different types of particles
• Partcles are in constant motion
• The particles in a substance move faster as it temperatures increases
• particles attract eachother
• particle theory of matter is a way of understand how matter behaves based on the idea that everything is made up of tine particles
• scientific inquiry is the process of how scientists study the world and purpose explanation based on the experients conducted
• question: ask a question about something

  hypothesis: experiment with an educated guess to answer the question

  experiment: test your guess

  conclusion: document your observations

  communication: does this answer your hypothesis?
• the states of matter are the different forms that different phases of matter can take, characterized by the arrangement and motions of particles
• solid particles are close in pattern, strong attractive forces, and vibrate in fixed positions
• liquid particles are fairly close together in groups, weaker attractive force, and particles move around and slide past one another
• gas particles are very far apart, have very weak attractive forces, and move apart from other particles
• solid to gas is sublimation
• liquid to gas is evaporation
• gas to liquid is condensation
• solid to liquid is melting
• liquid to solid is solidification
• physical property: characteristic of a substance that can be observed or measured without changing the substances chemical composition
• phys property eg: colour, density, texture, volume, smell
• chemical property: characteristic of a substance that describes its ability to undergo chemical reactions or change in substance
• chem property eg: flammability, toxicity, corrosiveness, combustibility
• physical change is when a substance undergoes a modification in its form or state of matter without changing its chemical structure. particles may get closer or farther apart but the particles remain un changed. (easy to reverse)
• chemical change is when a substance changes completely, elements or compounded rearrange to produce a new substance (difficult to reverse)
• chem change clues: colour change, new odour, heat/light produced, gas produced, precipitate forms
• density is the amount of matter within a certain space. density is a characteristic of a physical property. density can also be used to identify a subject.
• the equation for density : D = M/V
• the equation for mass : M = DV
• the equation for volume : V = M/D
• units for density:

  kilograms per m3

  grams per cm3
• when you freeze a liquid, its atoms or molecules get closer together, such that the solid is more dense then the liquid
• different substances have different densities
• the denstiy of water is 1g/mL or 1g/cm3
• freezing water into ice is an exception, this is caused by the unusual property of water that cold water is most dense at 4c
• an object that is denser than its surrounding area will sink
• an object that is less dense compared to its surroundings will float.
• matter is anything that has mass and takes up space
• matter is made up of mixtures and pure substances
• pure substances are made out of elements and compounds
• elements can NOT be chemically broken down, are apart of the periodic table

  eg: oxygen, chlorine, helium, hydrogen
• compounds CAN be chemically broken down

  eg:H2O(water), CO2(carbon dioxide), NaCl(table salt and sodium chlorine)