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Grade 10 (IB) Science Notes - SNC2D5
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Compiled notes from Grade 10 Sciences (chemistry, biology/ecology, physics) along with diagrams and tips & tricks :)
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Chemistry NotesLesson 1: Introduction to Matter
Everything is composed of matter!
- Everything that has mass and volume (occupies space) is matter.
- Mass: how much matter is in an object
- Measured in grams (metric) or pounds (imperial)
- Volume: how much space is occupied by an object
- Measured in cubic units (cm2) or litres (mL, L)
- Matter can be any state (solid, liquid, gas)
Changes of State
- Adding or removing heat from an environment may affect the state of a substance
- Temperature terms:
- The temperature in which a substance boils is called the boiling point
- The temperature in which a substance freezes is called the freezing point
- The temperature in which a substance melts is called the melting point
- Note: the freezing and melting points are the same!
Particle Theory of Matter
1. All matter is made up of tiny particles
a. Different substances are made up of different particles
2. All particles have spaces between them
a. Solid particles have very small spaces between them
b. Liquid particles have more spaces between them
c. Gas particles have very large spaces between them
3. Particles are in constant random motion
a. Types of motion include vibration, rotation, sliding past one another and moving in all directions
b. Particles move faster as temperature increases
4. Particles attract one another
a. Solids have a strong force of attraction
b. Liquids have a weaker force of attraction
c. Gases have a very weak force of attraction
Particles and Heat
- Heat is energy!
- Heating a substance makes the particles more energetic and so the particles move faster
- This weakens the attraction between particles
- If enough energy is added, the particles may even break free from each other, resulting in a change of
state
Classifying Matter
,Lesson 2: Physical and Chemical Properties
Physical Properties:
- Characteristics of a substance that can be observed or measured (and do not involve the ability of one
substance to react with another substance)
Properties of water
- Cohesion: The ability for water to stick on itself
- Adhesion: The ability of water to stick onto other things
- Both properties aid in the process of water moving up the stem of plants
Qualitative Physical Properties Quantitative Physical Properties
- Can be observed through your senses - Is a number value and may need to be measured
E.g. physical state, odour, colour, texture, lustre, solubility E.g. mass, volume, temperature
Common Physical Properties
Property Description
Colour and lustre The light a substance reflects give it colour and lustre
(shine)
Conductivity The ability of a substance to conduct electricity or heat
- A substance that conducts is a conductor
- A substance that doesn’t conduct is an insulator
Density The amount of mass in a given volume of a substance
Ductility Any solid that can be stretched into a long wire is ductile
[DO NOT CONFUSE WITH MALLEABILITY!!]
Hardness A substance's ability to resist being scratched
- Measured on the Mohl’s Hardness Scale (1-10)
Malleability A substance that can be pounded or rolled into a sheet is
said to be malleable
[DO NOT CONFUSE WITH DUCTILITY!!]
Viscosity The resistance of a fluid to flow (how thick a substance
is)
Optical clarity Describes the ability of light to pass through
- Transparent: fully passes through
- Translucent: partially passes through
- Opaque: doesn’t pass through
,Chemical Properties
- Describes if and how a substance reacts with another substance; describes what a substance does when it goes
through a chemical change
- E.g. flammability, ability to remove rust, ability to absorb/emit heat or light in a chemical reaction,
combustibility, reactivity, ability to form a precipitate (a solid that forms in a reaction with two
solutions)
Physical Change vs Chemical Change
- Physical change: a change in the physical properties that does not involve the formation of a new substance
- E.g. change of shape (folding, crumpling), change of state, combinations of separate things (chocolate
chip cookies)
- Chemical change: when a substance reacts with another substance to produce a new substance(s) as a result of
chemical reactions
- E.g. baking powder and vinegar, burning candle, food rotting
Evidence Of Chemical Change
1. Energy is produced or absorbed (but not as a result of an external heat source): changes in temperature, flame
is produced
2. Change of colour: an unexpected change of colour may mean new substances formed
3. Change of odour: new substances gives off a smell
4. Presence of gas: bubbles form that are not from boiling or heating
5. A solid precipitate forms: liquids combine but a sold appears
Characteristic Properties
- A physical or chemical property that is unique to that particular substance
- Can be used to identify unknown substances
- E.g. freezing, boiling and melting point
- Freezing point: temperature at which a substance turns from liquid to solid
- Melting point: temperature at which a substance turns from solid to liquid
- Boiling point: temperature at which a substance forms bubbles of vapour that escape into the
air (liquid to gas)
- E.g. 2: pure substance vs. mixture
- Combining substances (mixtures) results in a freezing and boiling point that is different from
with substances alone
- E.g. salt and water combined results in but freezing points being lowered
Density Calculations:
- Uses units mass/volume (e.g. g/ml, g/L)
- Density = Mass/Volume
- Mass = Density x Volume
- Volume = Mass/Density
Lesson 3: Developing the Atomic Theory
All matter consists of atoms.
- Atoms are the smallest part of an element that has all properties of that element
- It consists of three particles known as the subatomic particles
- Atomic theory: study of the nature of atoms and how they combine
Three Subatomic Particles
, - Proton (p+)
- Positively charged, similar mass to neutron
- Mass: 1836
- Found in nucleus
- Neutron (n0)
- No charge, similar mass to neutron
- Mass: 1837
- Found in nucleus
- Electron (e-)
- Negatively charged, small mass
- Mass: 1
- Located around nucleus
Developing Atomic Theory
Scientist Idea / Discovery
Democritus (440 BCE) - Hypothesised that breaking down rock into
powder, then grinding the powder, would reduce
it into tiny bits of matter (atoms) that couldn’t
be broken down more
- Called them “atomos”
John Dalton (1808) 1. All matter is made of small, invisible particles
called atoms
“The Billiard Ball Model” 2. All the atoms of one element are identical in
(atoms are like small spheres - each element has a properties such as size and mass
unique atom with a specific mass) 3. Atoms of different elements have different
properties
4. Atoms of different elements can combine and
form new substances
J.J. Thomson (1857) - Researched the idea that atoms are made of
(subatomic) particles
“The Plum Pudding Method” or “Chocolate Chip Cookie - Experimented on electric currents in a glass
Model” tube
(the raisins/chocolate chips are electrons, the dough are - Concluded that an atom has both electrons and
protons) protons “scattered around”
Ernest Rutherford (1909) - Predicted that atoms were everywhere
- Experimented by shooting positively charged
alpha particles into atoms of thin gold foil
- While most atoms went through, 1 in
100,000 bounced back
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