Matter and Energy Study Guide

  1. Broad classes of matter: Substance and Mixtures

a. Substance has a definite composition and mixtures have a varied composition from sample to sample.

  1. Compounds are two or more substances chemically combined and mixtures are two or more substances physically combined.
  2. Homogenous mixtures are substances that are soluble (mix well) with one another. Observe one phase.

Heterogenous mixtures are substances that are insoluble in one another. Do not mix well and because of that you can observe multiple phases.

  1. a. chex mix: hetero mixture

b. Helium : element

c. Air : homo mixture

d. Baking Soda: compound

  1. Classify as physical or chemical property

Soluble- P

Flammable-C

Spoils-C

Density-P

Condensation-P

Neutralizes-C

  1. Intramolecular forces are the forces within a single compound that hold the atoms together. Also called chemical bonds. They are affected during a chemical change. (combustion, digestion, growing, etc.)

Intermolecular forces are the forces that hold a group of compounds together. They are affected during a physical change. (melting, evaporation, condensation, etc.)

6.

Types of Changes / Physical or Chemical / Forces Affected:
Intermolecular or Intramolecular Forces
Iron rusting / C / intra
Water boiling / P / inter
Sugar dissolving / P / inter
Melting butter / P / inter
Neutralizing an acid / C / intra
Burning food / C / intra
Making popsicles / P / inter
Cutting aluminum foil / P / inter
Combustion of fossil fuels / C / Intra
  1. Physical separation techniques: extraction, distillation, chromatography, and filtration
  2. Filtration because separating a solid from a liquid.
  3. Distillation because separating two liquids based on boiling points.
  4. a. Heat energy is the energy that flows between two objects of different temperature.
  5. Heat energy alters the speed of particles and the strength of intermolecular forces
  6. Heat energy that affects the speed of particles can be measured using a thermometer.
  7. Energy and Temperature Conversions:
  1. 5.7 calories (cal)
  2. 958 Joules (J)
  3. 82,500 cal
  4. -247.4 oC
  5. 518 K
  6. 94 0C

12.

Phase Change / Strength of Intermolecular Forces / Heat energy / Type of Process
Melting butter / Inter forces decrease / absorbs / endothermic
Deposition of water vapor / Inter forces increase / release / exothermic
Salt water freezes / Inter forces increase / release / exothermic
Sublimation of copper / Inter forces decrease / absorb / endothermic
Condensation of water vapor into dew / Inter forces increase / release / exothermic
  1. During melting, evaporation, and sublimation particles absorb energy, speed up, and the intermolecular forces are weakened. During condensation, freezing, and deposition the particles release energy, slow down, and intermolecular forces are strengthened.

14. Matter is always conserved during physical and chemical changes. During physical changes the distance between the particles increase and during chemical changes you have the same atoms, they just rearrange chemically to produce new substances. Energy is associated with all changes. It is also conserved. If the system increaseses by 10 J, then that means the surroundings decreases by 10 J.