year 8 science semester 2

• What is the arrangement of particles in a solid?

  regular and close together

  
• What is the arrangement of particles in a liquid?

  random and close together

  
• what is the arrangement of particles in a gas?

  random and far apart

  
• what is a chemical change?


  a change where a new substance is formed and the chemical composition of the substances are changed
• what happens to the chemical bonds in a chemical change?

  bonds are broken and new bonds are formed, breaking chemical bonds take energy
• what is a physical change?

  a change in which the form or appearance changes, but no new substances are formed, includes changes of state of matter
• what is the particle speed (KE) of solids?

  low kinetic energy
• what is the particle speed of liquids?

  medium kinetic energy
• what is the particle speed of gases?

  high kinetic energy
• what is the volume of a solid?

  definite/fixed
• what is the volume of a liquid?

  definite/fixed
• what is the volume of a gas

  indefinite/unfixed
• what is the shape of a solid

  definite/fixed
• what is the shape of a liquid?

  indefinite/unfixed
• what is the shape of a gas?

  indefinite/unfixed
• is a solid easily compressed?

  no
• is a liquid easily compressed?

  no
• is a gas easily compressed

  yes
• what is the strength of the particle bonds in a solid?


  strong
• what is the strength of the particle bonds in a liquid?


  medium
• what is the strength of the particle bonds in a gas?

  weak
• what is the movement of particles in a solid?

  vibrate in a fixed position
• what is movement of particles in a liquid?

  slide past each other
• what is the movement of particles in a gas?

  move quickly in all directions
• what are some indicators of a chemical change?

  formation of bubbles (gas has been produced)formation of an odour (new product has been produced)formation of a precipitate (solid has been produced)permanent colour change
• what are reactants?


  the substances involved in a chemical reaction, left side of the arrowiron + oxygen -> iron oxide
• what are products?


  substances produced by a chemical reaction, right side of the arrow

  iron + oxygen -> iron oxide
• what are white blood cells

  white blood cells are involved in protecting the body against both infectious disease and foreign invaders
• what are red blood cells

  no nuclei and contain haemoglobin to transport oxygen, biconcave shape
• what are platelets

  blood components that contribute to the blood-clotting process, stops bleeds and thickens blood
• what is plasma

  liquid portion of blood, water-based solutions
• what organs make up blood cells


  bone marrow
• what is haemoglobin

  protein in red blood cells that carries oxygen around the body
• what is the ratio of RBC to WBC in the human body

  600:1
• what is an artery

  A blood vessel that carries oxygenated blood away from the heart, has thick muscular walls and elastic walls to push blood to the capillaries
• what is a vein

  a vessel that carries deoxygenated blood to the heart, has valves to prevent back flow of deoxygenated blood
• what is a capillary

  links blood vessels, takes in things carried by blood and transports it to tissue cells, where gas exchange in the lungs occurs, many capillaries to increase surface area, have thin walls to allows things to pass through it easier
• what happens when arterioles dilate?

  loss of excess body heat (person appears red)
• what happens when arterioles constrict?


  save body heat (person appears pale)
• what is the cause of coronary heart disease (heart attack), strokes and varicose veins

  Strokes: built up plaque or a blood clot blocks the flow of blood to the brain

  Heart attack: plaque buildup in the wall of the arteries that supply blood to the heart