Nico's CHEM 107 ARONSON

Gasoline

A complex mixture of mainly alkanes (single bonded hydrocarbons) with 7-9 carbon atoms.

Branching

The process of changing a hydrocarbon by removing a carbon atom to create a new branch.

Octane rating

A measure of how controlled the explosion of a fuel is.

Ethanol

A type of alcohol made from corn.

Stoichiometry

The study of quantitative relationships in chemical reactions.

Limiting reactant

The reactant that is fully consumed in a chemical reaction.

Excess reactant

The reactant that remains after a chemical reaction has completed.

Impurities

Substances that hinder reactions from reaching their theoretical yield.

Percentage yield

A calculation of the efficiency of a reaction, expressed as (actual yield / theoretical yield) x 100%.

Titration

A technique used to determine the concentration of a substance by limiting the limiting reactant.

NO2

Nitrogen dioxide, a primary pollutant from cars.

Reactive free electron

An electron that contributes to the reactivity of a molecule, often causing problems in reactions.

Gas properties

Characteristics of gases, including expansion to fill volume, low density, variable density, thorough mixing, and dramatic volume changes with temperature.

Universal gas constant (R)

A constant used in gas equations, with values of 0.08206 L atm mol-1 K-1 and 8.314 J mol-1 K-1.

Pressure

The force exerted per unit area.

Units of pressure

Measurements including 1 torr = 1 mm Hg, 1 atm = 760 torr, and 1 atm = 101,325 Pa.

Trace analysis

The detection of chemicals at extremely low levels.

Non-destructive testing

Techniques that do not damage or decompose samples.

Microscopy and spectroscopy

Techniques used in trace analysis that exploit the unique properties of different elements.

Speed of light (C)

A constant value of 3 x 10^8 m/s.

Wave equation

The relationship C = frequency * wavelength.

Photoelectric effect

The phenomenon where light striking a metal surface causes the ejection of electrons.

Energy transfer

The process by which energy from light is transferred to electrons in a metal, allowing them to break free.

Ideal Gas Law

Ideal Gas Law

The Ideal Gas Law is a fundamental equation in chemistry that describes the behavior of ideal gases. It is expressed as:

[ PV = nRT ]

Where:

• ( P ) = Pressure of the gas

• ( V ) = Volume of the gas

• ( n ) = Number of moles of the gas

• ( R ) = Ideal gas constant (8.314 J/(mol·K))

• ( T ) = Temperature in Kelvin

This law combines Boyle's, Charles's, and Avogadro's laws, providing a comprehensive relationship between pressure, volume, temperature, and amount of gas.

1 torr ≈ atm (atmospheres)

1 torr is approximately equal to 0.000987 atmospheres (atm).

1 torr ≈ mm/inHg (millimeters / inches of mercury)

1 torr = 1 mmHg (millimeter of mercury)

1 torr is approximately equal to 0.7500616 inches of mercury (inHg).

torr

Torr

Torr is a unit of pressure, defined as 1/760 of an atmosphere, equivalent to approximately 133.322 pascals.

c to kelvin

To convert Celsius (°C) to Kelvin (K), use the formula:

[ K = °C + 273.15 ]

For example, to convert 25°C to Kelvin:

[ K = 25 + 273.15 = 298.15 , K ]

celsius to farenheit

To convert Celsius to Fahrenheit, use the formula:

[ F = 9/5C + 32 ]

Where:

• ( F ) = temperature in Fahrenheit

• ( C ) = temperature in Celsius

moles to grams to molar mass relationship

The relationship between moles, grams, and molar mass is defined by the formula:

[ grams = moles x molar mass ]

Where:

• Moles (n) is the amount of substance.

• Grams (g) is the mass of the substance.

• Molar Mass (M) is the mass of one mole of a substance (g/mol).

STP conditions (standard temperature and pressure)

STP Conditions:

• Standard Temperature: 0 degrees Celsius (273.15 K)

• Standard Pressure: 1 atmosphere (101.325 kPa or 760 mmHg)

STP is commonly used as a reference point in chemistry for gas calculations.

Ideal Gas Constant (R)

The Ideal Gas Constant (R) is a fundamental constant used in the ideal gas law, which relates pressure, volume, temperature, and the number of moles of a gas. Its value is:

• R = 8.314 J/(mol·K) (joules per mole per kelvin)

• R = 0.0821 L·atm/(mol·K) (liters atmospheres per mole per kelvin)

• R = 62.36 L·torr/(mol·K) (liters torr per mole per kelvin)

The appropriate value of R depends on the units used in the calculations.

1 mol of Ideal Gas, volume at STP

1 mol of an ideal gas has a volume of 22.7 L at STP.

Kinetic Molecular Theory

Kinetic Molecular Theory

• Definition: A theory that explains the behavior of gases in terms of particles in constant motion.

• Key Points:

  • Gas particles are in continuous, random motion.

  • The volume of gas particles is negligible compared to the volume of the container.

  • Collisions between gas particles are elastic, meaning no energy is lost.

  • Average kinetic energy is directly proportional to the temperature of the gas in Kelvin.

Gay-Lussac's Law

Gay-Lussac's Law states that the pressure of a gas is directly proportional to its absolute temperature when the volume is held constant. Mathematically, it can be expressed as:

[ P1/T1 = P2/T2 ]

where ( P ) is pressure, ( T ) is the temperature in Kelvin, and the subscripts 1 and 2 refer to two different states of the gas.

Avogadro's Law

Avogadro's Law

• Definition: At constant temperature and pressure, equal volumes of gases contain an equal number of molecules.

• Formula: ( ​V1/n1​​=​ V2/n2​​ ) (where ( V ) is volume and ( n ) is the number of moles).

• Implication: This law implies that the volume of a gas is directly proportional to the number of moles of the gas, provided temperature and pressure remain constant.

Boyle's Law

P1​⋅V1​=P2​⋅V2​

• P1​ is the initial pressure (30.0 psi),

• V1V_1V1​ is the initial volume (1.55 mL),

• P2P_2P2​ is the final pressure (643.6 psi),

• V2V_2V2​ is the final volume (which we need to calculate).

bar (unit of pressure)

1 bar is equal to 100,000 pascals (Pa) or approximately 0.9869 atmospheres (atm).

Conversion:

• 1 bar = 100 kPa

• 1 atm ≈ 1.01325 bar

Summary:

• 1 bar ≈ 0.9869 atm

• 1 atm ≈ 1.01325 bar

kinetic energy formula

The formula for kinetic energy (KE) is:

[ KE = 1/2mv^2 ]

Where:

• ( KE ) = kinetic energy

• ( m ) = mass of the object (in kilograms)

• ( v ) = velocity of the object (in meters per second)

Limiting reactant

Limiting Reactant

The limiting reactant in a chemical reaction is the substance that is completely consumed first, limiting the amount of product formed. It determines the maximum yield of the reaction. To identify it:

1. Calculate moles of each reactant.

2. Use stoichiometry to determine how much product can be formed from each reactant.

3. The reactant that produces the least amount of product is the limiting reactant.

Percent yield

Percent Yield is a measure of the efficiency of a chemical reaction. It is calculated using the formula:

[Percent Yield=(Actual Yield/Theoretical Yield​)×100]

• Actual Yield: The amount of product obtained from a reaction.

• Theoretical Yield: The maximum amount of product that could be formed based on stoichiometry.

A percent yield of 100% indicates a perfect reaction with no losses.

Planck's constant

Planck's Constant

• Symbol: ( h )

• Value: ( 6.626 x 10^-34 J*s )

• Significance: Fundamental in quantum mechanics, relates energy of a photon to its frequency:[ E = h \nu ]where ( E ) is energy, ( h ) is Planck's constant, and ( \nu ) is frequency.

The Dilution Equation

The Dilution Equation

The dilution equation is used to calculate the concentration of a solution after dilution. It is expressed as:

[ C1V1 = C2V2 ]

Where:

• ( C1 ) = initial concentration

• ( V1 ) = initial volume

• ( C2 ) = final concentration

• ( V2 ) = final volume

This equation helps in determining how much solvent to add to achieve a desired concentration.

Boyle’s law

Boyle's Law states that for a fixed amount of gas at constant temperature, the pressure of a gas is inversely proportional to its volume.

Formula:

P1V1 =P2V2

Where:

• P1​ and P2​ are the initial and final pressures.

• V1​ and V2​ are the initial and final volumes.

Key Point: As volume increases, pressure decreases, and vice versa, assuming constant temperature.

L to Mols

1 = 22.4 L (in STP)

Mols to grams to molar mass relationship

Moles = Grams / Molar Mass​

grams to liters

1 liters / 1,000 grams