1
Q
Matter
A
Anything that has mass or takes up space
2
Q
Atom
A
The smallest unit of matter
3
Q
Element
A
A substance made up of only one type of atom
4
Q
Molecule
A
A structure made of two or mote atoms bonded together - can be same or different elements
5
Q
Compound
A
A substance made up of two or more different types of atoms chemically bonded together
6
Q
Mixture
A
Impure substances that have two or more different types of substance
7
Q
What is in the nucleus, and what charges?
A
NUCLEUS is positively charged, with protons (positive) and neutrons (no charge)
8
Q
What is the name of the fixed energy levels electrons orbit the nucleus at?
A
SHELLS or ORBITALS
9
Q
What charge is an atom?
A
NEUTRAL -> no. protons = no.electrons
10
Q
Location of proton, neutron, electron
A
Proton + Neutron = NUCLEUS
Electron = SHELLS
11
Q
John Dalton time in history
A
1766-1844
12
Q
John Dalton contribution to atomic model
A
Atomic theory -> all substances break down into elements that have the same proportions, atoms of different elements vary in size and mass
13
Q
John Dalton experiment completed
A
No physical experiment -> deductive reasoning based off laws and observations, experiments on properties of gas, compounds
14
Q
Joseph John Thomson time in history
A
1856-1940
15
Q
Joseph John Thomson major contributions
A
ELECTRON -> first to suggest internal structure of the atom, are small and are negative charged
16
Q
Joseph John Thomson experiment completed
A
Plum pudding model -> sphere of positive charge with negatively charged electrons embedded in it (like raisins in a pudding)
17
Q
Ernest Rutherford time in history
A
1871-1937
18
Q
Ernest Rutherford major contributions
A
Atoms consisted largely of empty space, with few electrons, most mass concentrated in centre ‘nucleus’, alpha particles passed through gaps, but bounced back from dense, positively charged nucleus
19
Q
Ernest Rutherford experiment
A
Short small positively charged alpha particles at sheet of gold foil, found that some particles bounced back, SHOULD NOT (thinly dispersed positive charge not enough to disperse particles at any place)
foil was like a NET, with a large mesh
20
Q
Niels Bohr time in history
A
1885-1962
21
Q
Niels Bohr major contributions
A
Stated that electrons orbited nucleus at fixed energies, distances. Could jump between levels but not exist in space between
22
Q
Scientific Model
A
Description of a natural phenomenon that scientists can use to make predictions
23
Q
What is a good model?
A
As accurate as possible and as simple as possible (powerful but easy to understand)
24
Q
Benefits of models
A
Simplifies complex ideas, useful for learning, teaching, sharing ideas, universal language for science
25
What makes up a compound?
Only molecules, not single atoms
26
What makes up an element?
Either single atoms or molecules of the same atom
27
Atoms of different elements differ in...
The number of protons (atomic number)
28
NUMBER OF NEUTRONS
MASS NUMBER - NUMBER OF PROTONS (ATOMIC NUMBER)
29
The higher the electron shell...
The more energy it has, the further away it is from the nucleus
30
For the first 20 elements, how many electrons are on the first 4 shells?
2, 8, 8, 2
31
Electron shells are filled from the...
Inside out
32
What do the groups on a periodic table show?
How many electrons are on their outer shell
33
What do the periods on a periodic table show?
How many shells there are
34
What is the first group on the periodic table called?
Alkali metals
35
What is the second group on the periodic table called?
Alkali earth metals
36
What is the seventh group on the periodic table called?
Halogens
37
What is the eighth group on the periodic table called?
Noble gases
38
Why does the Lewis dot diagram only show the outer electrons?
These are the ones that actually take part in chemical reactions
38
What does the Lewis Dot diagram show?
Shows how many electrons are on the outer (valence) shell
39
When atoms react together
Electrons are either transformed or shared
40
When an atom loses or gains an electron, it becomes
Charged
41
A charged electron is called an
Ion
42
What can ions be?
They can be either positive or negative -> positive ions are called cations, and negative ions are called anions
43
How do the different types of ions occur?
If electrons are gained, it becomes negative. If electrons are removed, it becomes positive
44
When a metal and non-metal react, electrons are transferred. Each atom becomes an ion. Which is which?
The metal becomes the positive (cation) and the non-metal becomes negative (anion).
45
What happens when the non-metal and metal are attracted together?
They are bonded together in an ionic bond.
46
When the ionic compound is formed, it must be neutral overall, therefore...
The charges need to be balanced
47
What is the difference between covalent and ionic compounds?
Covalent compounds are when the atoms share their electrons to have a full shell, while ionic compounds are when electrons are transferred between them so that they have full shells
48
What is a polyatomic ion?
When more than just one cation and anion bond together -> they act as anions or cations themselves instead of separately (NOT NEUTRAL)
49
What is the chemical formula and charge of Hydroxide?
OH^- (polyatomic anion)
50
What is the chemical formula and charge of Nitrate?
NO3^- (polyatomic anion)
51
What is the chemical formula and charge of Carbonate?
CO3^2- (polyatomic anion)
52
What is the chemical formula and charge of Sulfate?
SO4^2- (polyatomic anion)
53
What is a way to remember the polyatomic ions?
OH No! Cats Smell
OH -> Hydroxide (OH^-)
No -> Nitrate (NO3^-)
Cats -> Carbonate (CO3^2-)
Smell -> Sulfate (SO4^2-)
54
Rules for naming ionic compounds (metal and non-metal)
1. Name the metal first
2. Shorten the name of the non-metal
3. Add the suffix to the non-metal (eg. -ide)
55
What if the metal can have multiple valency, how do you know which metal ion is present?
1. The suffix -ic or -ous is added
2. The valency is indicated in brackets with roman numberals (copper(I))
56
What does a salt compound consist of?
A metal ion and a non-metal ion or polyatomic ion
57
What is a covalent bond?
When two non-metal atoms share a piece of electrons
58
Rules for naming covalent compounds
1. If Hydrogen is present, it is named first
2. If no Hydrogen is present, the solid non-metal is named first
3. If only 2 elements, 2nd is shortened and suffix '-ide' is added
4. If more than 2 elements, first is named, followed by name of polyatomic ion
59
Naming covalent compounds prefixes
If there are only two elements, use the prefixes 'mon', 'di', 'tri', 'tetra', 'penta', 'hexa,' etc, on the name of the second element
60
When do you add the prefix '-mono' in covalent compounds
Never on the first element, only on the second element when there is one of them
However, if there is Hydrogen at the front, don't add -mono to the second element
61
The pH scale measures...
How alkaline (basic) or acidic a substance is
62
What is neutral, acidic, or basic?
7 is neutral, 0-6 is acidic, 8-14 is basic
63
What happens when chemicals are mixed with water?
They can become alkaline or basic
64
Two examples of everyday acidic substances
Lemon juice, vinegar
65
Two examples of everyday basic substances
Laundry detergent, ammonia
66
Are chemical reactions involving acids are bases important?
YES, they occur everywhere, even inside the body
67
What does corrosive mean?
They react with solid substances, eating them away
68
Are acids or bases corrosive?
They both are
69
Properties of acids
Releases hydrogen ions when dissolved in water, good conductor of electricity, sour, produces hydrogen gase when reacting with metals
70
Properties of bases
Releases hydroxide ions when dissolved in water (ALKALIS), good conductor when aqueous, bitter, soapy texture
71
When mixed with water, acids...
Release hydrogen ions -> weaker acids release less ions, stronger acids release more ions
72
If a base can release hydroxide into water, it is an...
Alkali
73
Caustic soda is corrosive and can...
Break down hair, fat, and vegetable matter
74
What is the pH scale?
Potential of hydrogen, is a logarithmis scale.
If the number is lower, it has more hydrogen than hydroxide ions. If the number is higher, it has more hydroxide than hydrogen ions.
75
What is an indicator?
A chemical that can change colours depending on the presence of particular ions in a solution
76
What are indicators generally derived from?
Plant matter, usually either mildly acidic or basic in nature
77
What is universal indicator?
An indicator made by mixing multiple indicators together, so it can test a wide range of pH values
78
What is a pH meter
An electronic device that can test pH - needs to be calibrated before use
79
What is dissociation
When acids and bases are placed in a substance with water, they break down into ions
80
What happens when acids dissociate?
H+ ions are created
81
What happens when bases dissociate?
OH- ions are created
82
What happens in the neutralisation process?
Acids and bases are added together and the H+ and OH- ions react to form H2O (neutral)
83
Strong vs Weak acids
Strong acids release all their hydrogen ions into solution, weak acids release very few hydrogen acids into solution
84
Even though two solutions can have the same concentration of acids, they can have a...
Very different concentrations of hydrogen ions (and pH) depending on the strength of the acid
85
Examples of strong and weak acids
Strong -> hydrochloric acid, nitric acid, sulfuric acid
Weak -> acetic acid (vinegar), citric acid, lactic acid
86
Concentrated vs Dilute acids
Refers to the amount of solute in the solution.
If there is a lot of solute per unit of solvent, it is concentrated. If there is little solute per unit of solvent, it is dilute
(often written as M, molarity)
87
What is the difference between concentration and strength of an acid?
The concentration is how much of an acid is in the substance, while the strength of an acid is how many of its ions release into the solution
88
Testing Acid + Metal -> Salt + Hydrogen
Pop test to see if there is presence of hydrogen
89
Testing Acid + Carbonate -> Salt + Water + Carbon Dioxide
Limewater test to see if there is presence of carbon dioxide
90
Testing Acid + Base -> Salt + Water
Neutralisation, if you mix an acid and a base and universal indicator shows green (neutral on pH scale)
91
How does Acid + Base -> Salt + Water
The acid gives its H+ ions, the base gives its OH- ions, forming water. The rest forms a salt
92
What is the pop test?
Putting a lit splint near the mouth of a test tube in which there was a reaction, if it pops there is hydrogen
93
How does the pop test work?
Hydrogen is highly flammable, and when they bring the lit splint near the hydrogen, it reacts with the oxygen due to the heat, and energy is released suddenly, producing a small explosion
94
What is the limewater test?
It is when you bubble a gas through limewater, and if it turns milky, there is carbon dioxide
95
How does the limewater test work?
The carbon dioxide mixes with the limewater and makes calcium carbonate, which is insoluble, forming a white precipitate and making the solution milky
96
Neutralisation reactions are often....meaning...
Exothermic, they produce heat as they progress
97
Atoms are never created or destroyed during chemical reactions...
They are just rearranged
98
How are atoms rearranged during chemical reactions to form new substances?
Old bonds break and new ones form
99
Is it safer to neutralise a substance with a hydroxide or a carbonate?
A carbonate
100
Why is it safer to neutralise a substance with a carbonate?
Carbonates are weak bases, so if too much is used, the excess is a relatively harmless substance. However, if too much Hydroxide is used, the excess is a strong, caustic, dangerous alkaline solution. Carbonates are also LESS EXOTHERMIC
101
Chemical symbols for:
Hydrochloric Acid
Nitric Acid
Sulfuric Acid
Hydrochloric Acid -> HCl
Nitric Acid -> HNO3
Sulfuric Acid -> H2SO4
102
Naming salts:
First part comes from base, alkali, or metal carbonate
Second part comes from acid -> nitrate, sulfate, chloride
103
A chemical reaction is...
the rearranging or atoms to make a new product
104
Examples of chemical reactions in living things
Photosynthesis and Cellular Respiration
105
Formula for Photosynthesis
Water + Carbon Dioxide (+ Light) -> Glucose + Oxygen
106
Formula for Respiration
Glucose + Oxygen -> Carbon Dioxide + Water (+ Energy (ATP))
107
The states of matter
(s) -> solid
(l) -> liquid
(g) -> gas
(aq) -> aqueous, dissolved in water
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