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Science Grade 9 Academic Exam > Chemistry > Flashcards

Chemistry Flashcards

(40 cards)

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0
Q

Solid

A

Hold particles close together in rigid shape

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1
Q

Particle Theory

A
  1. All matter is made up of tiny particles that have empty spaces between them
  2. Different substances are made up of difference kinds of particles
  3. Particles are in constant random motion
  4. The particles of a substance move faster as its temperature increases
  5. Particles attract each other
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2
Q

Liquid

A

Particles move faster as it gets hotter, gaining more energy.

When there’s enough thermal energy, particles start sliding past each other because attraction between particles can no longer hold them together

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3
Q

Gas

A

If heating continues, particles gain so much energy they fly apart

Particles so far apart their forces of attraction have little effect on behaviour

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4
Q

Purpose of Alloys

A

Solder (tin&lead) used to join metal components together such as wires and pipes -quickly solidifies to firmly hold parts together

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5
Q

Alloys Associated Hazards

A

Lead poisoning causes irreversible damage to brain, kidneys, heart, reproductive organs especially in growing children

Many have been replaced with less hazardous materials

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6
Q

Physical Properties of Common Substances

A 
Lustre
Optical Clarity
Brittleness
Hardness
Malleability
Ductility
Electrical Conductivity
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7
Q

Quantitative Physical Properties

A

Temperature, Height, Mass

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8
Q

Density

A

Mass / Volume

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9
Q

Density graphs

A

As density increases, line gets steeper

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10
Q

Physical vs. Chemical Properties

A

Physical - substance characteristics determined without changing composition of substance

Chemical - substance characteristics determined with changing composition of substance and one or more new substances are produced

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11
Q

Physical Change

A

Composition of substance remains exactly same, no new substances are made

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12
Q

Chemical Changes

A 
Colour
Odour
Gas production (bubbles visible not caused by heating)
Precipitate production (new solid seen, often powdery)
Energy change (change in temperature/light)
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13
Q

Characteristic Physical Properties

A

Freezing Point: liquid to solid

Melting Point: solid to liquid

Boiling Point: liquid to gas

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14
Q

Element

A

Pure substance can’t be broken down into simpler chemical substance by any chemical/physical means

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15
Q

Compound

A

Pure substance composed of two or more different elements that are chemically joined

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16
Q

Properties of Metals

Study These Flashcards
A

Lustre
Malleable
Ductile
Conductor

17
Q

Properties of Non-Metal

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A

Usually gas/dull powdery solid

Usually poor conductors of heat & electricity

18
Q

Useful Properties of Chemical Elements: Potassium

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A

Plant foods i,e., oranges and bananas have good sources of potassium, important to function all living cells

19
Q

Useful Properties of Chemical Elements: Calcium

Study These Flashcards
A

Builds strong bones and teeth

20
Q

Useful Properties of Chemical Elements: Strontium

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A

Builds strong shell in coral

21
Q

Useful Properties of Chemical Elements: Magnesium

22
Q

Useful Properties of Chemical Elements: Helium

23
Q

Useful Properties of Chemical Elements: Neon, Krypton, Argon, Xenon

Study These Flashcards
A

Glowing neon signs

24
Useful Properties of Chemical Elements: Chlorine
Chemical weapon during World War I Safely killing bacteria from swimming pools
25
Useful Properties of Chemical Elements: Iodine
Disinfect scrapes & cuts (usually dissolved in alcohol)
26
Useful Properties of Chemical Elements: Bromine
Increase brightness & operating life of bulb
27
5 Atomic Models
1807 John Dalton - Atom Billiard Ball Model 1897 JJ Thomson - Electron Plum Pudding 1909 Ernest Rutherford - Nucleus & Proton Gold Foil Experiment (Tested thomsons) Niels Bohr - Neutron Bohr Model Bohr-Rutherford Model - Electron Orbits
28
John Dalton | Billiard Ball Model
Matter made of tiny, indivisible particles called atoms, resembled billiard ball Atoms of an element are identical Atoms of different elements are different Atoms are rearranged to form new substances in chemical reactions but are never created/destroyed
29
JJ Thomson | The Electron 'Plum Pudding'
Atoms contain negatively charged electrons If atom is neutral, rest of atom must be positively charged Electrons are evenly distributed in atom, like raising in plum pudding
30
Ernest Rutherford | Gold Foil Experiment
Atoms are mostly empty space Positively charged centre is surrounded by negatively charged electrons Centre of atom (nucleus) has positive charge - contains most of atom's mass but occupies very small space Nucleus is what made some particles bounce back during experiment
31
Niels Bohr Bohr Model Neutron
Studied light produced by hydrogen atoms when excited by thermal energy or electricity Electrons occupy fixed orbits around nucleus Each electron in orbit has definite amount of energy Farther the electron is from nucleus, greater its energy Electrons can jump to different orbits, releasing energy as light
32
Bohr-Rutherford Model | Electron Orbits
Consists of positively charged protons and neutrons in nucleus of an atom Negatively charged electrons orbit nucleus Explained observations of light emitting by hydrogen atom Central nucleus and orbiting electrons at different electron orbits
33
Patterns in Periodic Table
Elements in same chemical family have similar properties As you go down each family, number of electron orbits increase - a new orbit is added w/ each new row Within each family, all atoms have same number of electrons in their outermost orbits Reactivity of alkali metals increase as you go down group 1 as the furthest outermost electron from the nucleus has the weakest attraction, it's more likely to be lost.
34
Alkali Metal Properties
``` Shiny Silvery Soft Highly reactive Low density Can float on water ```
35
Alkaline Earth Metal Properties
Shiny Silvery Not as soft or reactive as alkali metals
36
Noble Gases Properties
``` Low density Colourless Odourless Tasteless Glow brightly when electrical current is passed through Non-toxic excluding radon ```
37
Halogen Gases Properties
Very reactive Rarely found in elemental form Often form compounds with alkali metals Poisonous in large amounts
38
Molecular Compound
Molecule that consists of two or more different elements Ex: Water (H2O) Sugar (CHO) Methane, Propane (CH)
39
Ionic Compound
Compound that consists of positively and negatively charged ions ``` Ex: Iron + Oxygen (Iron Oxide) Sodium Chlorine (Sodium Chloride) ```

Science Grade 9 Academic Exam (4 decks)

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