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Chemistry Flashcards

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1
Q

What is chemistry?

A

The study of the properties of matter and the changes matter undergoes

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2
Q

What are caustic materials?

A

Materials that will burn or corrode organic tissue

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3
Q

What are the 5 rules of PMOM?

A
  1. All matter is made of tiny atoms
  2. These atoms are constantly moving
  3. These atoms have spaces between each other
  4. These atoms attract and repel
  5. Warmer atoms move faster than colder ones
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4
Q

How is matter classified?

A
  • Matter (1)
  • Pure (2) Mixture (2)
  • Element (P3), Compound (P3), Homogenous (M3), Heterogenous (M3), Colloid (M3)
  • Suspension (MHt4), Mechanical Mixture (MHt4), Solution (MHm4)
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5
Q

What is the difference between heterogenous and homogenous?

A

In homogenous mixtures they are evenly distributed and you cannot differ based on sight, while heterogenous mixtures they are not evenly distributed and you can differ composing substances by looking

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6
Q

What are pure substances? What is the difference between an element and a compound?

A

A pure substance is only composed of one uniform type of particle. An element has a singular atom as its uniform particle, while a compound has a molecule. An element cannot be broken down by chemical change, only nuclear.

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7
Q

What is a mixture?

A

A substance composed of two or more substances

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8
Q

What are suspensions?

A

Suspensions are heterogenous mixtures that will settle down over time. When mixed, they are initially uniformly distributed.

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9
Q

What are mechanical mixtures?

A

Mechanical mixtures are physically combined mixtures. They can be easily physically separated and are heterogenous. Mechanical mixtures have particle sizes > 1000 nm.

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10
Q

What are solutions?

A
  • Solutions are homogenous mixtures. The solute is dissolved in the solvent.
  • Solutions cannot be physically separated easily
  • Solutions have particle sizes < 1 nm
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11
Q

What are colloids, what are emulsions and what is the Tyndall effect?

A
  • Colloids are “homogenous” by definition but are heterogenous by classification.
  • They are not solutions as their particle size is 1000 nm > colloid > 1 nm
  • Emulsions are a type of colloid where a liquid is evenly distributed into a liquid
  • The Tyndall effect: If you focus light onto a colloid light will scatter while solutions will not
  • Examples of colloids: Milk, jelly, salad dressing, mayo
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12
Q

What is the difference between physical and chemical properties?

A

Properties that can be observed without using a chemical reaction are physical and the ones that do require a reaction are chemical. Chemical properties describe how a substance behaves with another.

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13
Q

What is the difference between physical and chemical changes?

A

A chemical change causes new substances to form while physical changes do not. Physical changes can be reversed more easily than chemical changes.

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14
Q

What are some signs that a chemical reaction has occurred?

A
  • Precipitate
  • Heat
  • Colour change (sometimes)
  • Used up starting material
  • Gas bubbles
  • Change hard to reverse
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15
Q

Who are alchemists and which are some of the famous ones?

A

Supernatural believers who are also early chemists/pharmacists.
- Francis Bacon –> scientific method for experimental evidence
- Robert Boyle –> Elements can form compounds

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16
Q

What is the Law of Conservation of Mass?

A

Before and after the reaction, the total mass of the reactants and the products are equal (Antoine Lavoisier)

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17
Q

What is the Law of Definite Composition?

A

Compounds are pure substances that contain two or more elements in a fixed proportion

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18
Q

What is electrolysis?

A

The process of separating compounds by electrifying them

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19
Q

What is Dalton’s Atomic Theory?

A
  • All matter is made of atoms
  • Atoms cannot be split, created or destroyed
  • Atoms of the same element are identical (same isotopes and e-)
  • Compounds are made when atoms link together in fixed proportions
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20
Q

History of atomic models

A
  • 1897: Thompson’s pudding model (e- in mass of +)
  • 1911: Rutherford’s planetary model (electrons away but no orbit)
  • 1913: Bohr’s model (Electrons have orbits called shells)
  • Today (Schrödinger+Heisenberg+Louis de Broglie): Electron cloud (Randomized probable area where electrons could be found)
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21
Q

What is the difference between a law and a theory?

A

Laws describe/predict what happens, while theories explain why it happens. Laws are formed by observing general patterns in action. (It happens so much so repetitively that we believe it will happen again)

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22
Q

What are axioms and theorems?

A

An axiom is a universally accepted concept (e.g. 1+1=2). Without it, nothing would make sense, so it does not need proof.
A theorem is only for math. It shows a step-by-step explanation how X gets to Y etc. and is all proven logically (deductive) and rigorously.

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23
Q

Law vs Theorem

A
  • Laws everywhere while theorems mostly just math
  • Laws can be changed due to new discoveries but theorems cannot
  • Laws are not completely deductive
  • Laws cannot be rigorously proved easily
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24
Q

Models and Observations

A
  • Model: Simplified simulation of phenomenon to represent complex relationships or predict outcomes
  • Observations: Raw data extracted by our senses or tools or experiments.
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25
Scientific Method
Observations, Questions, Research, Hypothesis, Experiments. If explains: Law/Theory If not: New hypothesis, new experiments
26
What are element symbols?
Symbols for elements; Usually a capital letter with sometimes a following undercast
27
Who was the father of the periodic table? When did he publish it? How many were there in that initial model?
Dmitri Ivanovich Mendeleev; 1869; Around 60. He organized them by ordering atomic mass.
28
What are metals?
They are shiny (when pure) and are malleable and ductile (e.g. iron)
29
What is the difference between malleability and ductility?
Malleability is the ability to be rolled into thin sheets, while ductility is being rolled into a string (without breaking) (e.g. nickel)
30
What are nonmetals
- Elements that are usually brittle and have poor ductility (e.g. helium) - Dull - Poor conductors of heat but may conduct electricity
31
What are metalloids?
- Both properties of metals and nonmetals - May conduct electricity but not heat - Boron, Silicon, Germanium, Arsenic, Antimony, Tellurium
32
What is a chemical family?
- Group of elements that share similar properties - Same column in the periodic table - Have same amount of electrons in outer shell but not every electron with same amount is in the group (e.g. nickel not in noble gases) (Electron configuration; shell model too simple for it)
33
What are alkali metals?
Metals with one electron in outer shell and are very reactive; Oxidation usually 1+. Corrosive to tissue
34
What are alkaline earth metals and what are their properties?
Metals that are insoluble in water and unchanged by heat. They are fairly reactive but not as much as the alkalis. Oxidation: Usually 2+. Irritating/Hazardous.
35
What are transition metals and what are their properties?
- Metals with stronger metallic bonds which makes them harder - CAN BE MAGNETIC - Less reactive - Multiple oxidation states (e.g. Fe2+, Fe3+, Cu1+, Cu2+)
36
What are triels and their properties?
- Boron group (Group 13) - Common oxidation state: 3+
37
What are tetrels and their properties?
- Carbon Group (Group 14) -Common oxidation states: 4+, 4-
38
What are pnictogens and their properties?
- Nitrogen group (group 15) - Common oxidation states: 3-, 3+, 5- (many) - Varied toxicity (less than chalcogens except for arsenic)
39
What are chalcogens and what are their properties?
(Oxygen group 16) - Usual (but not as usual) oxidation: 2-. - Reactive and toxic (some) but not as much as halogens. - Some allotropy (O2, O3, S4, S6, S2) -
40
What is a halogen and what are their properties?
Extremely reactive non-metals with a 7 in outer shell. Oxidation: 1-. They are mostly toxic (poisonous) and lethal.
41
What are noble gases?
Gases with electron shells already filled so they do not react as much (stable)
42
Properties of reactive nonmetals?
- Highly electronegative (gain) - Lower melting and boiling points - Poor conductors - Tendency to form acids - High ionization (hard to remove electron)
43
Properties of post-transition metals?
- "Poor" metals because of being softer, weaker and less conductive as the transition metals - Less oxidation states - Poor catalysts - Lighter and more malleable - Lower boiling points and melting points
44
What is atomic mass?
Average mass of an atom of each element (e.g. Chlorine 35.45). Unit: amu (1.67*10^-24g), 1/12 mass of C-12 atom
45
What is atomic number?
The number of protons in an atom of a certain element
46
What is mass number?
Total amount of protons and neutrons in an atom
47
What is a period?
A row in the table
48
What are chemical formulas?
Scientific ways to write chemical reactions using numbers, symbols and element symbols (Follows law of conservation of mass) e.g. Fe(s)+CuCl2(aq) --> Cu(s) + FeCl2 (aq) (Aqueous or hydrous)
49
What is a molecule? How do they differ from compounds?
A group of atoms chemically bonded together (a compound). Compounds have DIFFERENT types of atoms (eg O2 is still a molecule but not a compound, classified as diatomic)
50
What is a binary compound?
A compound made of two different elements
51
Ionic vs molecular compounds
- Ionic transfers while molecular shares electrons - Attraction weaker in molecular so molecular compounds have lower boiling and melting points - No free electrons in molecular so poor conductor - Molecular: Nonmetals; Ionic: 1 metal + 1 nonmetal - Molecular cannot be ionized, if has charge is polyatomic ion
52
What is a precipitate?
A solid product in a liquid environment
53
What is an ion and how do ionic compounds work?
An ion is a charged group (or single) of particles. Conducts electricity and will bond with oppositely charged ions to form an ionic compound. - (The metal loses electrons while the nonmetal gains them)
54
Polyatomic ions?
Ions with more than one atom (e.g. (CO3)2-
55
Multivalent ions? Multivalent metal ions?
Some elements can take different oxidation states (e.g. Fe (+2, +3), Cu (+1, +2), N (+3, -3, -5), P, Cl (-1, +1, +3, +5, +7), S (2,4,6). The metal ones have a special name.
56
If elements are in the same column of the table, what does that mean?
Similar properties (not necessarily in groups 13-16)
57
Why are ionic solutions conductive?
When dissolved in water or melted, the ions split, and if energized can carry charges to electrodes, creating current
58
How to name ionic and molecular compounds?
(Metal first) [E1] [E2 end -ide] - Prefixes to write ratio (mono only used on 2nd) - Usually molecular uses prefix more than ionic
59
What is a chemical reaction?
When two or more substances reorganize their atoms to form different substances
60
Reactants and products
Reactants are the things before and products are the things after
61
Chemical equations
x + y --> z (or other) - Precipitate in product? Down arrow next to it - Triangle sign on arrow for heat - Conditions written on top or below arrow - Catalysts above - Gas formed with no gaseous reactants? Up arrow - Law of Conservation of Mass To account for energy that is important sometimes you must write +light or +heat or something else - After the terms you sometimes must write subscript of state of matter
62
What are chemical bonds?
Bonds that make atoms act as a whole
63
How to break chemical bonds?
Add energy (reaction releases as well after)
64
Exothermic reactions?
Heat is going OUT (hence EXO)
65
Endothermic reactions?
Heat is going IN (absorbed; ENDO --> IN)
66
Reaction rate
How fast a chemical reaction occurs. Stirring, heating up, decreasing size of singular particles, changing concentration, or adding a catalyst can increase rate
67
What is corrosion and rust? How do they differ?
(Rust: type of corrosion, iron oxide) Corrosion: Oxidation of metals/minerals in air + moisture, they lose strength - 4Fe+ 3O2 -> 2Fe2O3 (hematite) - 2Fe+O2 -> 2FeO (wustite) - FeO + Fe2O3 -> Fe3O4 (magnetite)
68
What is a catalyst?
A substance that makes the reaction rate faster but does not affect final output (E.g. MnO2 or KMnO3 or CaO)
69
What is an enzyme?
A natural organic catalyst made by organisms
70
What is an inhibitor?
Something that slows down the reaction rate without affecting final output (e.g. cyanide (yes, cyanide), carbon monoxide, etc.)
71
How to prevent corrosion?
Galvanize metals by coating with zinc

Science 9 (5 decks)

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