Solids, liquids and gases

• What is density defined as?

  Mass per unit volume
• How is density expressed mathematically?

  Density is expressed as $\rho =$$\frac{m}{V}$
• What units are used for density?

  Kilograms per cubic meter or grams per cubic centimeter
• Why is density a specific value for each material?

  Because the same material always has the same density
• If an unknown material has a mass of 2.41 kg and a volume of 125 cubic cm, what is its density?

  19.3 g per cubic cm
• What determines whether an object will float or sink in a liquid?

  The object's density compared to the liquid's density
• What happens to a block of aluminum in water?

  It sinks because its density is greater
• How does a block of ice behave in water?

  It floats but is partially submerged
• What is the first step in measuring the density of a regular object?

  Measure the mass using an electric balance
• How do you calculate the volume of a cube?

  Using $V =$$\text{side}^3$
• What is the formula for the volume of a cylinder?

  $V =$$\pi r^2 h$
• How do you find the volume of a sphere?

  $V =$$\frac{4}{3} \pi r^3$
• What is the method to measure the volume of an irregular object?

  Use water displacement in a measuring cylinder
• How do you calculate the density of a stone?

  $\rho =$$\frac{m}{V}$
• What is the pressure defined as?

  Force per unit area
• What is the equation for pressure?

  $P =$$\frac{F}{A}$
• If a cuboid has dimensions 3 m, 2 m, and 5 m, what is its contact area when lying on a 3 m by 2 m surface?

  6 m²
• What is the pressure exerted by a cuboid weighing 500 N on a contact area of 6 m²?

  83 Pascal
• What is the pressure exerted by the same cuboid on a contact area of 15 m²?

  33 Pascal
• How does pressure change with contact area while force remains constant?

  Pressure increases as contact area decreases
• How does a wooden plank affect pressure on soft ground?

  It increases surface area, reducing pressure
• What happens to pressure in a liquid at greater depths?

  Pressure increases with greater depth
• What is the equation for pressure in a liquid?

  $P =$$\rho g h$
• What does the pressure in a liquid depend on?

  Density of the liquid and depth
• If the density of mercury is 13,600 kg/m³ and the height of the mercury column is 0.74 m, what is the air pressure?

  100,000 pascals
• What are the three states of matter?

  Solid, liquid, and gas
• How are particles arranged in a solid?

  Close together in a regular pattern
• What is the behavior of particles in a liquid?

  They can move and slide past each other
• How do gas particles behave compared to solids and liquids?

  They move around randomly at high speeds
• What is internal energy?

  Sum of kinetic and potential energies of molecules
• How does temperature affect the kinetic energy of molecules?

  Kinetic energy increases as temperature increases
• What happens to potential energy as the separation between molecules increases?

  Potential energy increases with increased separation
• What is the process called when a solid changes to a liquid?

  Melting
• What is the process called when a liquid changes to a gas?

  Boiling or evaporating
• What is the process called when a gas changes to a liquid?

  Condensation
• What is the process called when a liquid changes to a solid?

  Freezing
• What are the properties of solids, liquids, and gases?

  • Solids: Strong intermolecular forces, definite shape and volume, particles vibrate in fixed positions.
  • Liquids: Weaker intermolecular forces, no definite shape but definite volume, particles can slide past each other.
  • Gases: Very weak intermolecular forces, no definite shape or volume, particles move randomly at high speeds.
• What is the relationship between temperature and kinetic energy in matter?

  • Kinetic energy increases with temperature.
  • Gases have greater kinetic energy than liquids.
  • Liquids have greater kinetic energy than solids.
• What are the changes of state in matter?

  • Melting: Solid to liquid.
  • Boiling/Evaporating: Liquid to gas.
  • Condensation: Gas to liquid.
  • Freezing: Liquid to solid.
• What is internal energy in matter?

  Sum of kinetic and potential energies