Matter and Energy

• Properties is the characteristics of the substance under observation.
• Properties can be either directly observable or the manner something interacts with other substances in the universe.
• Matter is the part of the universe that has mass and volume.
• Energy is the part of the universe that has the ability to do work.
• Chemistry is the study of matter.
• Physical Properties are the characteristics of matter that can be changed without changing its composition.
• Chemical Properties are the characteristics that determine how the composition of matter changes as a result of contact with other matter or the influence of energy.
• The boiling point of ethyl alcohol is 78°C. This is an example of Physical Property.
• Diamond is very hard. This is an example of Physical Property.
• Sugar ferments to form ethyl alcohol. This is an example of Chemical Property.
• The states of matter are: solid, liquid, and gas
• Liquid water takes the shape of its container.
• Physical Changes are changes to matter that do not result in a change the fundamental components that make that substance.
• Chemical Changes involve a change in the fundamental components of the substance.
• Iron is melted. This is an example of Physical Change.
• Iron combines with oxygen to form rust. This is an example of Chemical Change.
• Sugar ferments to form ethyl alcohol. This is an example of Chemical Change.
• Substances which can not be broken down into simpler substances by chemical reactions are called elements.
• Most substances are chemical combinations of elements. These are called compounds.
• Homogeneous is uniform throughout and appears to be one thing.
• Heterogeneous is non-uniform and contains regions with different properties than other regions.
• In Pure Substances:

  • All samples have the same physical and chemical properties
  • Constant Composition ⇒ all samples have the same composition
  • Homogeneous
  • Separate into components based on chemical properties
• In Mixtures:

  • Different samples may show different properties
  • Variable composition
  • Homogeneous or Heterogeneous
  • Separate into components based on physical properties
• Gasoline is a homogenous mixture.
• A stream with gravel on the bottom is a heterogeneous mixture.
• Copper metal is a pure substance (all elements are pure substances).
• Boiling Point is where distillation happens, the boiling point is the temperature at which the liquid turns into a gas.
• To separate the states of matter, the technique use is filtration.
• To separate the adherence to a surface the technique used is chromatography.
• To separate volatility the technique used is evaporation.
• Heat is a flow of energy due to a temperature difference.
• Exothermic is a process that results in the evolution of heat.

  • Example: when a match is struck, it is an exothermic process because energy is produced as heat.
• Endothermic is a process that absorbs energy.

  • Example: melting ice to form liquid water is an endothermic process.
• One calorie is the amount of energy needed to raise the temperature of one gram of water by 1°C.
• Units of Energy = joule
• The amount the temperature of an object increases depends on the amount of heat added (Q).
• The amount the temperature of an object increases depends on its mass.
• Specific Heat (s) is the amount of energy required to raise the temperature of one gram of a substance by one Celsius degree.
• Q=sxmxΔT is the formula for calculating the amount of heat.