Chemistry- Unit 1

Unit 1.1

Household Product Safety(HHPS)

Types of frames used around the symbols are

• Inverted Triangle- It means that the container is dangerous
• Octagon- It means the product inside the container is dangerous

Workplace Hazardous Materials Information System (WHMIS)

Pictograms	Name	The danger
	Exploding Bomb	Explosives, Self- reactives, Organic Peroxides
	Corrosion	Skin corrosion/burns, Eye damage, Corrosive to metals
	Flame Over Circle	Oxidizing gases, liquids and solids
	Gas Cylinder	Gases under pressure
	Enviroment	Aquantic toxicity
	Skull & Crossbones	Acute toxicity(fatal or toxic)
	Exclamation Mark	Irritant(eye & skin), Skin sensitizer, Acute toxicity,Narcotic effects, Respiratory tract irritant, Hazardous to ozone layer(non-mandatory).
	Health Hazard	Carcinogen, Mutagenicity, Reproductive toxicity, Respiratory sensitizer, Target organ toxicity, Aspiration toxicity.
	Flame	Flamemables,Pyrophorics,Self-heating, Emits-flammable gas, Self reactives, Organic peroxides.

Material Safety Data Sheet (MSDS) identifies the ==specific== chemical and physical hazards associated with the product.

Properties and Classification of Matter

Properties: describe the physical appearance and composition of a substance

==Physical== Properties include:

• Boiling or condensation point
• Melting or freezing point
• Malleability(capable of being altered or controlled by outside forces or influences.)
• Ductility(the ability of a material to be drawn or plastically deformed without fracture)
• Color, state, and solubility
• Crystal formation
• Electrical conductivity and magnetism

==Chemical== Properties describe how reactive a substance is

Chemical properties include:

• Ability to burn and flash point
• Behavior in air
• Reactions with water, acids, heat and litmus

Pure Substances and Mixtures

• Pure substances- All substances that make up the substance are identical, so its chemical and physical are constant. (element of compound)
  • Element- Pure substance that @@cannot@@ be broken down into an other substances
  • Compound- chemical combination of two or more elements in a specific ratio.
• Mixtures- Combination of two or more pure substances
• Hetereogenous Mixtures (different):
  • Mechanical Mixtures- different substances are visible
  • Suspentions- Where componets are in different states
  • Colloids- Suspended substances cannot be easily seperated
• Homogenous mixture(same throughout):
  • Solutions- seperate compounds are not visible;one substance is dissolved in another.

Chemical Reactions

Two important features of a chemical reaction are:

1. New substances with new physical and chemical properties are formed
2. Energy flows into or out of the system during a reaction.

To indicate a chemical change 2 or more of the following should occur:

• Heat or light is produced or absorbed
• the starting material is used up, or a new substance is produced
• There is a change in color
• A percipitate( solid) or bubbles(gas) formed in the liquid
• The change is difficult to reverse
• New odour forms

Atomic Models

1. Greek Theory- Proposed that matter could be composed of small, indivisble particles

2. John Dalton (Billiard Ball Theory)-

   • He rediscovered the atomic concept of matter
   • States the law of multiple proportions
   • When 2 or more elements form a series of Compounds form a fixed mass that have interger ratios of each other
   • Ex. Methane:CH4, has a 1:4 ratio of carbon:hydrogen
   • To behave in this manner atoms need to be formed

3. JJ Thompson (Plum Pudding or Raising Bun Model)-

   • Most famous for discovering the electron
   • Thompson worked with a Cathode Ray Tubes(CRTs) .
   • Cathode ray tubes showed that all atoms contain tiny negatively charged subatomic particles or electrons.
   • Thomson proposed the plum pudding model of the atom, which had negatively-charged electrons embedded within a positively-charged "soup."

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4. Rutherford (Planetary model)-

   • Rutherford fixed the problem in Thompson’s model
   • Rutherford designed an eperiment that helped fix the problem called the scattering experiment.
   • Alpha particles were expected to pass through the thin gold foil with little scattering.
   • Rutherford assumed that the alphas were interacting electrositcally with solid centers of the atom.
   • He discovered the nucleus with protons and neutrons.

5. Niels Bohr (Bohr Model)-

   • Bohr modified Rutherfors’s theory
   • He observed that electrons don’t orbit the nucleus but they exist with diffrent energy levels.

6. Schroedinger ( Electron Cloud or Quantum Mechanical Model)-

   • An elvolving model but currently thought of as a cloud of negative charges.

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