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CHEMISTRY-FY > S1-L1 Elements, Compounds & Mixtures > Flashcards

S1-L1 Elements, Compounds & Mixtures Flashcards

1
Q

What is “matter”?

A
  • Anything that has mass
  • all objects made of matter
  • single chemical substance/complex mix of substances
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2
Q

Outline the states of matter

A

-Solid/ liquid/ Gas

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3
Q

State the processes taking place when changing from a solid to liquid to gas and vice versa as well as solid to gas and gas to solid

A
  • melting–>vaporisation
  • condensation–>freezing
  • solid to gas–> sublimation
  • gas to solid–> deposition
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4
Q

What physical changes take place when changing from steam-water-ice and vice versa

A
  • condensing/liquefying–>freezing/solidifying

- evaporating/boiling–> melting/fusing

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5
Q

Define the following properties of matter:

1-Electrical conductivity 
2-Heat conductivity 
3-Desnity 
4-M. Point 
5-B. Point 
6-Refractive Index 
7-Malleability 
8-Ductility
A

1-Ability to transmit electricity-like copper use in electrical wiring
2-Ability to transfer heat energy-like aluminium saucepan
3-mas:volume ratio like lead weights
4-temp when solid turns to liquid-like 0 degrees for water
5-temp when liquid becomes gas-like 100 degrees for water
6-way light passes through material bent-like 1.33 for H2O
7-ability to be shaped via hammering-like gold jewellery
8-ability to shape via puling in to wire-like tantalum-dentist instrument

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6
Q

Define the property “intensive” and outline example(s)

A
  • Not dependent on amount of matter present
  • could use to identify substance
  • like density/ colour/ b. point
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7
Q

What are “extensive” properties and give some example(s)?

A
  • Dependent on amount of matter present

- like mass/volume/weight

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8
Q

Describe what “physical” properties are and how they arise

A
  • Observed by examining pure substance

- arise from molecular structure & intermolecular force’s strength

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9
Q

What are “chemical” properties and how do they arise?

A
  • Observed during chemical reaction

- Arise from e- distribution around atom’s nucleus–> particularly outer (valence) e-‘s

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10
Q

Outline and describe “pure” substances

A
  • Fixed set of physical + chemical properties
  • can’t separate via physical processes
  • properties not vary
  • can only change via chemical reaction
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11
Q

Briefly explain what a “mixture” is

A
  • 2 or more substances physical blend
  • variable composition
  • different properties for different compositions
  • can separate mixture in to separate components via physical process
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12
Q

Define an “element”

A
  • simplest form of matter which has unique properties
  • can’t split substance in to two/ more simpler substance via chemical method
  • ->like H or O
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13
Q

What is a “compound” and give an example?

A
  • compounds contains two/ more chemically bonded elements in fixed proportion
  • like H2O
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14
Q

What are “molecules” and describe them?

A
  • most matter made up of molecules/mixture of them
  • group of 2+ atoms joined together
  • element can exist as atoms/molecules but compounds made of molecules
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15
Q

Outline a summary of Dalton’s atomic theory

A
  • Elements combined in fixed ratios
  • all matter composed of atoms
  • different elements have different atoms types
  • ->can characterise by atomic weight/ all same elements identical
  • can create/destroy atoms
  • compounds composed of 2+ atoms chemically combined in fixed proportions
  • ->like H2O ratio: 2H + 1 O
  • chemical reactions rearrange atoms–>changing chemical combination so identity of atom changes.
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16
Q

Briefly explain the following properties of atoms:

1) Mass
2) Combining power

A

1) -Almost all atom’s mass contained in nucleus
- protons/ neutrons/ electrons
2) -ability to form chemical bonds
- also termed valency

17
Q

Structure of atom:

1) Describe the structure of the atom including the nucleus

A

1) -Proton (+) charged
- neutron uncharged
- nucleus surrounded by e-‘s (-) charged
- e-‘s in outermost orbital determine atom’s chemical and electrical properties

18
Q

Define the “nucleons” of an atom

A

-Is the n. of protons and neutrons in the nucleus which is the atom’s mass number

19
Q

Describe the meaning of “combining power”-valency

A
  • Ability of atom to combine with other atoms controlled by n. of e-‘s
  • ->which atom will give/take/share to form chemical compound
  • relates to n. of e-‘s AND electron’s spaces in atom’s electron shells
20
Q

What are “chemical symbols”?

A
  • abbreviation/short-hand form of chemical element used in formulae
  • consists of capital letter and sometimes followed by small letter
  • examples: H/ O/ He (Helium)
21
Q

Where are chemical names/symbols derived from and give some examples?

A
  • From their Greek/ latin names
  • examples:
  • Chlorine-Greek for yellowish green; Cl
  • Helium- Greek for sun; He
  • Calcium-Latin for lime; Ca
  • Carbon-Latin for charcoal; C
  • Iron- Anglo-Saxon; Fe (Latin)
22
Q

Define and describe “Relative Atomic Mass (Ar)”

A
  • Defined as mass of one atom of element divided by mass of 1/12 of atom of C-12
  • Ar of chemical element gives atom’s weight which is force makes when gravity pulls on it
  • written as subscript before atom’s symbol like 1^H
23
Q

Describe what “molecules” are

A
  • Unit of 2+ atoms held together by chemical bonds
  • contains atoms in defined proportions like water
  • -> 2 H and 1 O
24
Q

What is “molecular formulae”?

A
  • Show n. of atoms found in 1 molecule of substance
  • ->like sugar: glucose contains 6C’s/ 12 H’s and 6 O’s
  • ->written as C6H12O6
25
Q

Outline the terms “Relative Molecular Mass (Mr)”

A

-Gives mass of molecule relative to that of 12C atom which taken to have mass of 12

26
Q

What is the relative molecular mass formula and how do you calculate it (give an example)?

A
  • Mass of 1 molecule substance/ (1/2 X mass of 1 atom of C-12)
  • RMM calculated by summing atomic masses of atoms in molecule
  • Example: H2O- (2 x H) = H2O
  • -> (2 x 1) + (16)= 18
27
Q

Describe what a general mixture is

A
  • Variable composition
  • components retain characteristic properties
  • separable in to pure substances via physical methods
  • mixtures of different compositions may have widely different properties
28
Q

What does it mean when a mixture is described as “homogeneous”?

A
  • Single phase
  • same properties throughout mixture with uniform appearance
  • such as a solution
29
Q

Outline what a “heterogeneous” mixture is

A
  • Multiple phase
  • variable properties with non-uniform appearance
  • colloids visually homogeneous BUT microscopically heterogeneous
30
Q

Describe a “colloid”

A
  • Phase separated mixture in which one substance of microscopically dispersed insoluble/soluble particles suspended throughout another substance
  • sometimes dispersed substance alone called colloid but term refers to overall mixture
31
Q

Give a definition and description of a “solution”

A
  • Type of homogeneous substance formed when one substance dissolved in another
  • best mixed out of all “mixtures”
  • always has substance dissolved & substance which does dissolving
  • ->substance which dissolves solute
  • ->substance which does dissolving in solute
32
Q

What property does the separation of mixtures rely on?

A

-Use differences in physical properties

33
Q

Briefly outline the following basic separation techniques:

1-Filtration 
2-Crystallisation 
3-Extraction 
4-Distillation 
5-Magentisation 
6-Chromotography
A

1-select components by particle size (solid/liquid)
2-select components by solubility (solid from solution)
3-select components by solubility (solid/liquid from solution)
4-select components by b. point (liquid-liquid)
5-magnetic metal from other components
6-select components by affinity for stationary point

34
Q

What is “thin-layer chromatography”?

A
  • Technique used to separate non-volatile mixtures
  • performed on sheet of glass/ plastic/ aluminium foil
  • ->which coated in thin layer of adsorbent material like silica gell
35
Q

Outline a key use of thin-layer chromotography

A

-Analysis of common over counter (OTC) cough-cold prep

36
Q

Summary of lecture

A
  • Elements–>compounds
  • Atoms–>molecules
  • Symbols–> Formulae
  • Sum of Ar–> Mr

-Uniform properties–> yes–> fixed composition–>yes –> chemically decomposable–> yes –> compound

  • No uniform properties–> heterogeneous mixture
  • No fixed composition–> homogeneous mixture
  • Not chemically decomposable–> element

CHEMISTRY-FY (11 decks)

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