Module 1 Chemistry Notes: CAT Exam, Separation Techniques, Measurement, and Unit Conversions

CAT Exam and Grading System- The CAT exam covers content from sections $1.1.1$, $1.8$, and $2.1.1$.- The practice quiz for section $1.1$ may include material not yet fully covered in class.- CAT scores are manually transferred from Canvas ("Sands") and scaled.- The initial plan to make the CAT out of $15$ points is being adjusted because not all $15$ questions will be relevant to the material covered so far.- Current Scaling: Aim for approximately $4$ correct questions on the CAT. This would result in a score of $40$ points. For example, if you get $3$ questions right, you'll earn $30$ points; if you get $5$ questions right, you'll earn $50$ points.- The grading scale will gradually increase over time (e.g., next week it might be out of $80$ points or involve $20$ questions).- Score updates are not immediate; they occur after manual scaling.- Students are encouraged to view all $60$ questions on the CAT, answering those they can without anxiety about unfinished topics.- The "bronze career certificate" assignment has asterisks, indicating its deadline is flexible and will be moved every Saturday throughout the semester.

Candle Combustion Products and Separation Techniques

Substances Present in Candle Combustion and Air

• Solid Carbon (Soot): From incomplete combustion.- Nitrogen ($ext{N}<em>2$): From the surrounding air.- Carbon Dioxide ($ext{CO}</em>2$): Product of complete combustion.- Water ($ext{H}<em>2 ext{O}$): Product of complete combustion.- Carbon Monoxide ($ext{CO}$): Product of incomplete combustion.- Oxygen ($ext{O}</em>2$): Reactant from the air.- Argon ($ext{Ar}$): Noble gas from the air.- Wax: Unburnt candle material (specifically mentioned $ext{C}<em>{10}$ and $ext{C}</em>7 ext{H}_{14}$).

Reaction and Physical States

• Combustion: The extent of reaction (complete, partial, or none) depends on the availability of oxygen.- Physical States (at high temperature, during combustion process):

  • Smoke (Carbon): Solid

  • $ext{N}_2$: Gas

  • $ext{CO}_2$: Gas

  • $ext{H}_2 ext{O}$: Gas

  • $ext{CO}$: Gas

  • $ext{O}_2$: Gas

  • $ext{Ar}$: Gas

  • Wax: Gas (but prone to condense)

• Physical States (at room temperature):

  • Smoke (Carbon): Solid

  • $ext{N}_2$: Gas

  • $ext{CO}_2$: Gas

  • $ext{H}_2 ext{O}$: Liquid

  • $ext{CO}$: Gas

  • $ext{O}_2$: Gas

  • $ext{Ar}$: Gas

  • Wax: Solid

Step-by-Step Separation of the Mixture

Separation techniques rely on differences in physical properties like pressure and temperature.

Step 1: Filtration

• Procedure: Pass the hot mixture through a filter.- Separates: Solid carbon (soot) from the gaseous components.- Principle: Particle size. Solid carbon particles are much larger clusters of atoms compared to individual gas molecules.- Tool: A force wrench (or similar apparatus) can be used to contain and manipulate the hot mixture.

Step 2: Distillation (Cooling Down)

• Procedure: Gradually cool the remaining gaseous mixture.- Principle: Differences in condensation temperatures (the reverse of boiling points).- Order of Condensation:

  1. Wax and Similar Compounds: These compounds are hydrophobic (