Science (Chem) Flashcards
1
Q
Hypothesis:
A
Educated guess based on prior knowledge
2
Q
Law:
A
General statement based on extensive empirical data about what is happening
3
Q
Theory:
A
Explanation of observations in the law (often multitudes of law); theories can be tested a lot with results that can be true (used for predictions).
4
Q
Model:
A
Provides a mental picture for theory; may be word description, mathematical equation, diagram, physical model
5
Q
Indigenous Knowledge:
A
Oral tradition; knowledge gained from traditions, beliefs, experience with nature; passed on from one generation to the next.
6
Q
Empirical Knowledge:
A
Knowledge gained through experience; is proven through observations, science and experiments
7
Q
Scientific Method:
A
Scientific inquiry followed by a procedure:
- Purpose - (ask a testable question),
- Hypothesis - (make a probable prediction based off of prior knowledge, or logic),
- Materials - (chemicals, substances, and apparatus used), safety considerations,
- Procedure - (step-by-step description on how to perform investigation), diagram,
- Observations - (qualitative or quantitative observations/data),
- Analyze - (compare data, look for patterns to make predictions),
- Discussion questions - (make connections), and conclusions (summarise results, was hypotheses correct),
- Comments - (opinion on investigation).
8
Q
Particle Theory of Matter:
A
- All matter is made up of tiny particles.
- All particles of one substance are the same. Different substances are made up of different particles.
- The spaces between the particles are large compared to the sizes of the particles themselves.
- The particles are always moving. The more energy that particles have the faster they move.
- There are attracting forces among the particles. These forces are stronger when the particles are closer together.
9
Q
Matter:
A
The “stuff” of the universe; anything that has mass and occupies space (volume)
10
Q
Property:
A
A characteristic or quality used to describe matter (ex. Diamonds are shiny)
11
Q
Qualitative Property:
A
Properties that can be described using the 5 senses (ex. Sugar tastes sweet).
12
Q
Quantitative Property:
A
Properties that involve a measurement (ex. The volume of the liquid is 10).
13
Q
Physical Property:
A
Properties that do not involve the formation of a new substance - can be qualitative or quantitative
14
Q
Chemical Property:
A
Properties that DO INVOLVE the formation of a new substance: iron reacts with water to form iron oxide (rust)
15
Q
Physical Change:
A
A change that does not affect the chemical identity of a substance - the chemical composition stays the same but the form or state of the substance changes (ex. Melting ice into water).
16
Q
Chemical Change:
A
A change that DOES ALTER the chemical identity of a substance and as a result forms new substances that have different properties - the chemical bonds break, new bonds form, the chemical composition changes. Ex. raw egg becomes cooked;3 hydrogen molecules + 1 nitrogen molecule = 2 ammonia molecules
17
Q
Scientific inquiry is a way of learning which involves:
A
- Asking questions
- Making observations
- Proposing answers
- Testing those answers
18
Q
Brittleness:
A
When subjected to stress, it breaks without significant deformation. Breakability or flexibility. Example: glass is brittle.
19
Q
Clarity:
A
The ability to allow light to pass through an object. Opaque - wall, translucent - frosted glass, transparent - water.
20
Q
Ductility (metals):
A
Ability to be drawn or pulled into a finer strand ex. Copper can be drawn into thin wires therefore ductile.
21
Q
Electrical Conductivity:
A
Ability of a substance to allow electric current to pass through it ex. Copper is a conductor and plastic is not a conductor.
22
Q
Hardness:
A
Ability to resist scratch or be scratched by another substance ex. Wax has low hardness, diamonds have high hardness.
23
Q
Lustre:
A
Ability to reflect light; shiny or dull
24
Q
Malleability:
A
Ability of a substance to be hammered into thin sheets or to be molded ex. Glass is brittle, gold is is malleable - can be made into rings
25
Viscosity: (quantitative)
Measure of a fluid's internal resistance to flow ex. Honey has a high viscosity, water has a low viscosity.
26
Miscibility:
Ability of two substances to mix together (dissolve into) ex. Water and oil are not miscible.
27
Odour:
A distinctive smell ex. The odour of an unknown chemical.
28
Taste:
The sensation of flavour perceived in the mouth and throat on contact with a substance ex. Taste of pizza.
29
Texture:
The feel, appearance, or consistency of a surface or substance ex. Fuzzy carpet.
30
Colour:
The way an eye sees the light reflected off an object ex. Green trees (wavelengths of light being reflected).
31
Mass:
The measure of the amount of matter (kg/g/lbs).
32
Volume:
The amount of space that a substance or object occupies (m3).
33
Temperature:
The measure of hotness or coldness (Celsisus or Farenheit).
34
Boiling Point:
The temperature at which a substance changes state rapidly from a liquid to gas (celsius or fahrenheit). Ex. water becomes vapour.
35
Freezing Point:
The temperature at which a substance changes state from a liquid to solid m.p. and f.p. are the same temperature for substances. (celsius and fahrenheit).
36
Melting Point:
The temperature at which a substance changes state from solid to liquid. (celsius or fahrenheit).
37
Density:
A measure of how much mass is contained in a given unit volume of a substance (g/cm3, kg/L). Ex. The density of water is 1 gram per cubic centimetre.
38
What is a characteristic physical property of matter?:
A physical property that is unique to a substance and that can be used to identify that substance.
39
Why is knowing the melting points of metals important?:
It's beneficial for our safety; also so we know where certain metals can be used, and how they’ll be affected
40
How does salt melt ice and snow?:
Salt melts ice and snow because it lowers the freezing point of water.
41
Mass:
The amount of matter in an object. Measured with a scale in g/kg.
42
Length:
The distance of the longest side of an object. Use a ruler in cm.
43
Width:
The distance of the shortest side of an object. Use a ruler in cm.
44
Height:
The distance of the altitude of an object. Use a ruler in cm.
45
Volume:
The amount of space an object occupies. Measured in cm3 for regular shaped objects. l x w x h. Measured in litres for a liquid.
46
Density:
The mass per unit volume of a substance. Measured in g/mL or g/cm3.
47
Volume for a regular shaped object:
- Measure length, width, and height
- Calculate V = l x w x h
48
Volume for a small irregular shaped object:
- Displacement method with graduated cylinder
- Read the meniscus
49
Volume for a large irregular shaped object:
- Displacement method with overflow can
- Read the meniscus
50
1cm3 =
1mL
51
Calculating Slope
Equation:
(mass2 - mass1) / (volume2 - volume1) g/cm3
52
Slope:
Steeper the slope = greater the density
53
Grass Method:
Given, Required to Prove (RTP), Analysis, Solve, Statement
54
Given:
State given info with units of measure.
55
Required to Prove (RTP):
State what you have to solve for.
56
Analysis:
Write out the formula you are using.
57
Solve:
Substitute numbers into formulas to solve unknown (no words).
58
Statement:
Write a therefore statement.
59
Density=
Mass/Volume
60
Volume=
Mass/Density
61
Mass=
Density x Volum
62
Physical Property:
Is observed with the senses and can be determined without destroying the object. For example colour, space, mass, length, and odour.
63
Chemical Property:
Indicates how a substance reacts with something else. The original substance is fundamentally changed in observing a chemical property. For example, the ability of iron to rust is a chemical property. The iron has reacted with oxygen and the original iron metal is changed. It now exists as iron oxide, a different substance.
64
Solid to Liquid:
Liquidification
65
Liquid to Gas:
Evaporation
66
Solid to Gas:
Sublimation
67
Gas to Solid:
Deposition
68
Gas to Liquid:
Condensation
69
Liquid to Solid:
Solidification
70
Physical Change:
Any change NOT involving a change in the substance’s chemical identity. For example:
(1) any change of state. Moving between solid, liquid and gas involves only the amount of energy in the sample. There is no effect on the chemical identity of the substance. For example, water remains water no matter if it is solid, liquid, or gas.
(2) grinding (makes into smaller pieces) something into a powder. Or the reverse process of making a biggest lump of stuff, say by melting lots of small pellets of copper into one big piece.
71
Chemical Change:
Means that the reacting substance(s) are changed into NEW substances. The actual atoms involved remain, they are simply rearranged. Bonds break, atoms rearrange, new bonds form. For example: 2H2O makes 2H2 + O2 is a chemical reaction. Water broke down into hydrogen, and oxygen. Nothing changed, the atoms simply rearranged. Some new chemical bonds have broken (water), and new bonds formed (hydrogen + oxygen).
72
Signs that a chemical change has happened:
- A new colour appears
- Energy - heat or light is given off
- Bubbles of gas are formed
- A solid material called a precipitate forms in a liquid
- The change is difficult to reverse
73
FeCl3
Iron Chloride
74
NaOH
Sodium Hydroxide
75
HCl
Hydrochloric Acid
76
CaCO3
Calcium Carbonate
77
CuSO4
Copper Sulfate
78
H2O2
Hydrogen Peroxide
79
MnO2
Manganese Dioxide
80
Catalyst:
Substances that increase the rate/speed of a chemical reaction.
81
Chemical Equations:
- Chemical reactions can be written as chemical equations; starting substances are reactants and final substances are called products.
- In a chemical change, the total mass of products is equal to the total mass of the reactants.
- Number of atoms in reactants = same number of atoms in products
- Atoms have rearranged and new bonds have formed new substances.
- Example: H2 + O2 → 2H2O
82
Word Equations:
- Uses the names of chemicals involved in the reaction
- ex . Hydrogen + Oxygen → Water
83
Balancing Chemical Equations:
- If hydrogen and oxygen are involved, do hydrogen second last and oxygen last
- Coefficients multiply the total number of atoms
84
Types of Chemical Reactions:
- Synthesis Reaction
- Decomposition Reaction
- Single Displacement
- Double Displacement Reaction
85
Synthesis Reaction:
- Two or more elements combine to form a compound.
- A + B → AB
- Ex. Iron + Sulfur → Iron (II) Sulfide
86
Decomposition Reaction:
- A compound is broken into smaller compounds or elements.
- AB → A + B
- Ex. Electrolysis of water into oxygen and hydrogen gas
87
Single Displacement:
- One element is displaced from a compound by another element.
- A + BC → AC + B
- Ex. Zinc combines with hydrochloric acid and the zinc replaces the hydrogen
88
Double Displacement Reaction:
- Two compounds exchange bonds or ions in order to form different compounds.
- AB + CD → AD + CB
- Ex. Sodium Chloride + Silver Nitrate → Sodium Nitrate + Silver Chloride
89
Hydrogen -
H
90
Helium -
He
91
Lithium -
Li
92
Beryllium -
Be
93
Boron -
B
94
Carbon -
C
95
Nitrogen -
N
96
Oxygen -
O
97
Fluorine -
F
98
Neon -
Ne
99
Sodium -
Na
100
Magnesium -
Mg
101
Aluminum -
Al
102
Silicon -
Si
103
Phosphorus -
P
104
Sulfur -
S
105
Chlorine -
Cl
106
Argon -
Ar
107
Potassium -
K
108
Calcium -
Ca
109
Manganese -
Mn
110
Iron -
Fe
111
Cobalt -
Co
112
Nickel -
Ni
113
Copper -
Cu
114
Zinc -
Zn
115
Bromine -
Br
116
Krypton -
Kr
117
Rubidium -
Rb
118
Francium -
Fr
119
Cesium -
Cs
120
Lead -
Pb
121
Gold -
Au
122
Silver -
Ag
123
Iodine -
I
124
Polonium -
Po
125
Uranium -
U
126
Mercury -
Hg
127
Xenon -
Xe
128
Barium -
Ba
129
Matter:
Anything with mass and has a volume
130
Mixtures:
Made of two or more PURE SUBSTANCES (elements or molecules) not chemically combined; no reactions between substances; can be physically separated; most substances
- Can be separated into their components by chemical or physical means
- Properties are similar to properties of their components
131
Mechanical Mixtures (Heterogeneous)
- 2 or more pure substances
- Particles are not uniformly scattered
- Can see different particles
132
Solution (Homogeneous)
- 2 or more pure substances but looks and feels likes it is made of only one
- Particles are uniformly scattered
133
Mechanical Mixtures (Heterogenous):
Types
- Ordinary Mechanical Mixtures: stay mixed, do not settle ex. Granite
- Suspension: particles will separate with gravity ex. River water
- Colloid: particles will not separate with gravity (too small) ex. Mayonnaise, milk, glue
134
Pure Substances:
Made of only one kind of particle; cannot be separated by physical means
135
Atom:
Basic unit particle of matter; the periodic table of elements lists all the known types of atoms.
136
Molecule:
Two or more atoms are chemically bonded to make a unique particle of Matter
137
Element:
Pure substance that cannot be broken down into simpler substances (except in nuclear reactions); uniform all the way through (homogenous); made up of ONLY ONE kind of atom; the particles making up an element may be an atom or molecule depending on the element. Ex. Magnesium - Mg atoms; Bromine - Br2 atoms
138
Compound:
Pure substance that can be broken down chemically into simpler substances and contain two or more kinds of atoms - when chemically combined someway they can come together to form groups of atoms called molecules; always homogeneous (uniform); cannot be separated by physical means - needs chemical reactions; different properties than element it contains
- Ex. NaCl - sodium chloride (salt)
- Ex. carbon dioxide gas is made up of CO2 molecules
Carbon monoxide gas is made up of CO molecules
Glucose (type of sugar) is made up of C6H12O6 molecules
139
Diatomic Molecules:
- Have to be bonded with themself or another element
- H2 Br2 O2 N2 Cl2 I2 F2
- H. Bronclif
140
Atomic Theory of Matter (John Dalton):
1) All matter is made up of small particles called atoms.
2) Atoms cannot be created, destroyed, or divided into smaller pieces.
3) All atoms of the same element are identical in mass and size, but they are different in mass and size from the atoms of other elements.
4) Compounds are created when atoms of different elements link together in definite proportions.
141
The Changing Model of The Atom:
Democritus - Indivisible Particle:
- All matter can be divided into smaller and smaller pieces until it cannot be broken down further
- Suggested ‘atomos’ that means indivisible ‘cannot be cut’
- Also suggested: different atoms are different sizes, atoms are in constant motion, atoms are separated by space
142
The Changing Model of The Atom:
Aristotle - 4 elements:
- Rejected idea of the atom
- Everything made of 4 elements: earth, wind, fire, and water
143
The Changing Model of The Atom:
John Dalton - Billiard Ball Model:
1. All matter is made up of tiny particles, called atoms
2. Each element has its own kind of atom
3. All atoms of an element are identical
4. Atoms are rearranged to form new substances in chemical reactions BUT not created or destroyed by any ordinary means
- Envisioned atoms as small billiard pool ball
144
The Changing Model of The Atom:
JJ. Thomson - Plum Pudding:
- Atom is solid sphere of positively charged matter
- Negatively charged electrons embedded in solid sphere - evenly distributed
- Called plum pudding because the electrons are embedded in the solid sphere like the dried fruits are randomly scattered in the plum pudding.
145
The Changing Model of The Atom:
Ernest Rutherford - Electron Cloud:
- Thomson’s student
- Conducted gold foil experiment
- Small positive tiny core nucleus (proton)
- Rapidly moving electrons form an electron cloud around core
- Atom is mostly empty space
146
The Changing Model of The Atom:
James Chadwick - Planetary Solar System Model:
- Discovered the neutron (a particle) in the nucleus
- Neutrons add mass to the atom
147
The Changing Model of The Atom:
Neils Bohr Model - Orbital Model:
- Electrons move around nucleus in path or orbit
- Electrons in orbit have a definite amount of energy
- Electrons can move from one orbit to another by using or releasing energy
- Each orbit can hold a maximum number of electrons: 1st - 2, 2nd, - 8, 3rd - 8
148
Inside The Atom
There are over 200 subatomic particles that have been identified. The three fundamental subatomic particles are the proton, neutron, and electron.
- Nucleus
- Protons
- Neutrons
- Electrons
- Energy levels/shells/orbits
149
Nucleus:
- Tiny core of the atom
- Contains 99.9% of the mass of the atom
- It is 100,000 times smaller than the size of the atom
- Contains protons and neutrons
150
Protons:
- Has a positive charge
- Number of protons is equal to the number of electrons in the atom
- Has a mass of 1 amu (atomic mass unit) = 6x10-24 grams
- 1836 times heavier than an electron
- Protons are not lost or gained during a physical or chemical change
151
Neutrons:
- Has a neutral charge
- Provides essential matter for restabalizing the nucleus
- Too many or too few neutrons = nucleus falling apart
- Neutrons are not lost or gained during a physical or chemical change
152
Electrons:
- Has a negative charge
- Mass of 1/1836 amu
- Speed of 13,000km/h
- Travel about the nucleus a billion times/second
- Do not move in fixed orbits
153
Energy levels/shells/orbits:
- The energy of an electron determines its location within the electron cloud
- Each electron is restricted to an energy level or shell
- Electrons with less energy are found closer to the nucleus
- Electrons with higher energy are found further away from the nucleus
- Each energy level holds a certain amount of electrons
- The valence electrons in the outermost shell determines how the atom combines with other atoms - cause chemical reactions
154
Chemical Symbols:
- Swedish chemist Jons Jakob Berzelius proposed a system of chemical symbols (50 elements known at the time)
- New elements = person who found it can name the element
- Chemical formula uses symbols and subscript numbers - MgCl2
- Standard atomic notation - element symbol with atomic # (protons = electrons) and atomic mass (protons + neutrons) - round the mass
- Neutrons (protons subtracted from mass)
155
Alkali Metals (I):
Physical Properties
- Shiny; high lustre
- Silvery/silver/grey in colour
- Soft - hardness
- Conduct electricity + heat
- Low melting and boiling points
- Low density (less than 1g/ml will float)
- Solid
- Malleable and ductile
- Soft enough to cut with knife (not francium)
156
Alkali Metals (I):
Chemical Properties
- Highly reactive
- Reacts violently with water, thus they are stored in oil
157
Alkaline Earth Metals (II):
Physical Properties
- Medium lustre
- Differ in shades of colour (some silvery, some white)
- Conduct electricity and heat
- Higher melting and boiling points
- Higher density than group 1
solid
- Malleable and ductile
- Not as soft as group 1, cannot cut with knife
158
Alkaline Earth Metals (II):
Chemical Properties
- React readily
- Not as reactive as group 1 metals
- Burn bright colourful flames which are used for fireworks
159
Transition Metals:
Physical Properties
- Known for hardness (metal)
- Good conductors of electricity and heat
- High densities
- Solid
- Iron, nickel, and cobalt are the only elements known to produce a magnetic field
160
Transition Metals:
Chemical Properties
- As you move across left to right, they become less reactive
161
Chalcogens (VI):
Physical Properties
- Gases, solids - are soft
- As you move down family (column) melting points, boiling points, and densities increase - gas to solids
- As you move down family, elements become more metallic - colours vary
162
Halogens (VII):
Physical Properties
- Non-metals, low densities
- F and Cl - yellow-green
- Br - red/brown liquid
- Iodine and Astatine - violet/black solid
163
Halogens (VII):
Chemical properties
- Highly reactive - found in nature as compounds
- Some are poisonous
164
Nobel Gases (VIII):
Physical Properties
- Non metals - all gases
- Colourless and odourless gases
- All noble gases give off brightly coloured light when electricity pasts through it which makes them useful for decorative lights (Neon Signs)
165
Nobel Gases (VIII):
Chemical Properties
- Non toxic except for radon
- Non reactive or ‘inert’
166
Ionic Bonding:
- Electrons move from one outer shell to another
- Creates atoms that are NOT neutral
- Atoms gain or lose electrons to form a stable octet
- Charged ions - one positive - cations (gives electrons)
- Negative ions - one negative - anions (takes electrons)
- Will stay together because opposite charges attract
- Formed between metal, and non metal
- Form an ionic compound
167
Covalent Bonding:
- No transferring electrons
- Shells overlap to share electrons
- Involves uncharged atoms which form molecular compounds
- Non-metal and Non-metal
168
Bonding:
Both types of bonds are equally as strong but, ionic compounds are held together more firmly. The charges keep the molecule held together. Molecular compounds do not have any charges to hold molecules together; they have lower melting points.
169
Isotopes:
- Members of an element family that have the same number of protons and electrons, but different numbers of neutrons.
- Lighter isotopes = lighter mass than average
- Heavy isotopes = heavier mass than average
170
Chemical Nomenclature:
Ionic Compounds:
- The metal name is first, and it remains the same
- The nonmetal comes second, and the ending changes to ‘ide’
171
Chemical Nomenclature:
Molecular Compounds:
- The first element is the one that is farther to the left and or bottom of the periodic table
- The second element in the name is the one farther to the right and/or top with ending changed to the suffix ‘ide’
- 1 - mono, 2 - di, 3 - tri, 4 - tetra, 5 - penta, 6 - hexa, 7 - hepta, 8 - octa, 9 - nona, 10 - deca
