Module 2 - Foundations of Chemistry Flashcards by Tom Heeremans

What was the Plum Pudding Model?

The model that proposed that atoms were actually made up of negative electrons floating around in a “sea” of positive charge.

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What was Ernest Rutherford’s Gold Foil experiment, and what were the results?

Directing alpha particles towards a thin sheet of gold leaf, measuring direction + deflection of particles.
Most particles were not deflected, some were deflected at large angles, and some were deflected back towards the source.

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What are the relative masses of a proton, neutron, and electron?

1 for Proton
1 for Neutron
1/2000 for electron (basically 0)

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What are the relative charges of a proton, neutron, and electron?

1 for Proton
0 for Neutron
-1 for Electron

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What is an isotope?

A substance with the same number of electrons and protons as a certain element, but a different number of neutrons.

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What does atomic number mean?

Number of protons or number of electrons of a certain element.

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What does mass number mean?

Number of protons + Number of neutrons of an element.

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What is Relative Atomic Mass?

The weighted mean mass of an element relative to 1/12th of a Carbon-12 isotope.

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What is Mass Spectrometry?

Determining the mass of a molecule or isotope by measuring the mass to charge ratio of ions

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How does mass spectrometry work?

The spectrometer causes substances to become positive ions, and as they travel down the apparatus they are seperated based on mass and relative charge.

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How is mass/charge ratio shown?

m/z
m = mass
z = charge of ion (usually 1)

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What is the formula for Nitrate, Hydroxide, and Carbonate?

NO3 - = nitrate
OH- = Hydroxide
CO3 2- = Carbonate

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What is the formula for Sulfate and Ammonium?

SO4 2- = Sulfate

NH4 + = ammonium

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What is Avagadro’s Constant?

number of particles per mole, 6.02 x10^23

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what is the formula for mass, mols, and RFM?

Mols = Mass / RFM

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What is the empirical formula?

The simplest ratio of atoms within a chemical compound.

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What is the molecular formula?

The number of each atom that makes up a certain molecule

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What is the Ideal Gas Equation?

PV = nRT
P = pressure
V = volume
n = mols
R= gas constant (8.314 J/mol-1 K-1)
T = temperature

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How do you convert cm^3 to dm^3?

Divide by 1000

e.g. 24.0dm^3 = 24000cm^3

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What is the formula linking mols, concentration, and volume?

n = c x V

V in dm^3

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What does Concentrated mean?

large amount of solute per dm^3 in a solution

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What does Dilute mean?

small amount of solute per dm^3 in a solution

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What is a giant structure in a chemical equation?

When many atoms or ions join together in a repeating fashion.

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What is percentage yield?

The percentatge value of desired products created

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What is the equation for percentage yield?

percentage yield = actual amount of product (mols)/ theoretical amount of product (mols) x 100

Why would the percentage yield not be 100%?

- reactants may be impure - reaction may be at equilibrium and not complete - side reactions may occur, which creates by-products - seperation and purification may result in the loss of some of the product.

What is atom economy?

it describes the efficiency of the reaction in terms of all the atoms involved.

What is the equation for atom economy?

Atom economy = molecular mass of desired product / sum of molecular masses of all products x 100

How can atom economy benefit society?

By using processes with higher atom economy, we reduce the amount of chemical waste produced, which is harmful for the environment.

True or False - Addition reactions will always have an atom economy of 100%

True

True or False - Substitution or Elimination reactions will always have an atom economy of 100%

False - the atom economy will always be less than 100%, as there is always a waste product.

What is the formula for nitric acid?

HNO3

What is the formula for sulfuric acid?

H2SO4

What is the formula for Hydrochloric acid?

HCl

What is the formula for ethanoic acid?

CH3COOH

What is an Acid?

a proton donor with a pH less than 7, typically having H+ ions present

What is an Alkali?

a proton acceptor with a pH more than 7, typically having OH- ions present.

What is the difference between a strong and weak acid?

A strong acid fully dissociates with it's H+ ions, whereas a weak acid only partially dissociates with it's H+ ions.

What are examples of an Acid?

nitric acid, hydrochloric acid, citric acid, ethanoic acid, sulfuric acid, etc.

What are examples of an Alkali?

Sodium Hydroxide (NaOH), Potassium Hydroxide (KOH), Ammonia (NH3), etc.

What is a substance that can behave as an acid and a base called?

Amphoteric Substances - e.g. glycine, which has a carboxyl group that can donate a proton, and an amino acid group that can accept a proton.

What is a salt?

- cation usually a metal ion or ammonium ion (NH4 +) - anion usually derived from an acid - formula of a salt usually same as that of a parent acid.

How are salts formed?

When an acid is neutralised by a base, e.g. - carbonates - metal oxides - alkalis

What do the terms anhydrous and hydrated mean?

anhydrous - form containing no water hydrated - crystalline form containing water (e.g. copper sulphate can exist as either hydrated or anhydrous)

What is the dot formula?

shows the ratio between the number of compound molecules and number of water molecules within a crystalline structure.

What is a Titration?

measuring the volume of one solution that reacts with a measured volume of another solution.

What indicator do you use in a titration?

Methyl Orange, as it turns red in acidic solutions and yellow in basic solutions.

What is an oxidation number?

The number of electrons that an atom uses to bond with atoms of another element.

What is the oxidation number of an uncombined element

What is the oxidation number of combined oxygen

-2

What is the oxidation number of combined oxygen in peroxides

-1

What is the oxidation number of combined hydrogen

What is the oxidation number of combined hydrogen in metal hydrides

- 1 | e. g. LiH

What is the oxidation number of a simple ion

the same as the charge of the ion e.g. Na+ = +1 Mg2+ = +2

What is the oxidation number of combined fluorine

-1

What is the oxidation number of compounds

if it has an overall charge of 0, the oxidation number is 0

What is the oxidation number of molecular ions

the charge of the molecule | e.g. CO3 2- = -2

What is oxidation

The gain of oxygen, and the loss of electrons

what is reduction

The loss of oxygen, but the gain of electrons

What is a redox reaction

A reaction in which both oxidisation and reduction takes place

True or False: Reduction is a decrease in oxidation number, whereas Oxidation is an increase in oxidation number.

True