SCIENCE

• Solvent


  The substance that does the dissolving
• Water is a good solvent

  Due to its polarity and small molecular size
• Saturated solution


  A solution that cannot hold any more solute at room temperature
• Supersaturated solution


  Requires reducing the amount of solute
• Solution between two miscible liquids

  • Ethanol dissolved in water
• Physical change


  A change where the chemicals have properties identical to the chemicals before the change
• Chemical change


  A change where the chemicals have properties different to the chemicals before the change
• Heptane is always composed of 84% carbon and 16% hydrogen by mass
• Mass number


  The sum of the number of protons and neutrons in an atom's nucleus
• Reaction between substances W and Z

  1. Mass of W before reaction: 6.0g

  2. Mass of Z before reaction: 3.0g

  3. Mass of WZ after reaction: 9.0g
• Conditions that increase the rate of chemical reaction

  • Increased temperature and increased concentration of reactants
• Activation energy


  The minimum energy required to start a chemical reaction
• Glass of plain ice-cold water without ice


  Warms up faster than a glass of ice water with ice
• Solubility graph


  • Solubility of a substance in 300 cm3 water at different temperatures
• Electrolysis


  The process of using electricity to cause a chemical reaction
• Jacques Charles discovered Charles' law by studying the relationship between the volume and temperature of a gas at constant atmospheric pressure
• Charles' law


  V/T = constant (for a gas at constant pressure)
• If the volume of a gas at a certain pressure is halved


  Its temperature is doubled
• Temperature-volume relationship for a gas


  • Graph showing inverse proportionality between temperature and volume
• Inertia


  The tendency of an object at rest to stay at rest, and an object in motion to stay in motion
• Maron's bike ride


  Rode from 9:00 am to 10:30 am at an average speed of 15 kph
• Constant force


  The force exerted by the woman on the box is equal to the total force resisting the motion of the box
• When the woman stops applying a horizontal force to the box

  The box will continue moving at a constant speed for a while and then slow to a stop
• Frequency of motion of a mass-spring system

  Inversely proportional to the square root of the mass and directly proportional to the square root of the spring constant
• Velocity-time graphs


  • Showing different types of motion
• 0.20 kg block


  Mass of the block
• Spring constant


  20 N/m
• Initial stretch


  0.10 meters
• Time


  t = 0 seconds
• To increase the frequency of the motion

  1. Reduce the spring constant

  2. Decrease the mass of the block

  3. Increase the length of the spring

  4. Reduce the distance the spring is initially stretched
• Graph A shows a body moving at constant speed
• Graph B shows a body moving at high acceleration at the beginning then starts to lose acceleration towards the end
• Acceleration


  Due to unbalanced force
• Student B is twice as massive as student A


  Student B will reach the water sooner than student A
• Both students have the same gravitational potential energy
• Both students will have the same kinetic energy just before hitting the water
• Student B did twice as much work climbing the tower
• A feather falls from a certain height inside a vacuum tube is a case of uniformly accelerated motion
• A ball rolls along a frictionless plane at uniform speed is not a case of uniformly accelerated motion
• A coin falls from a certain height in air but air resistance is negligible is a case of uniformly accelerated motion