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)

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."

   

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.