Science (Chem) Flashcards
Hypothesis:
Educated guess based on prior knowledge
Law:
General statement based on extensive empirical data about what is happening
Theory:
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).
Model:
Provides a mental picture for theory; may be word description, mathematical equation, diagram, physical model
Indigenous Knowledge:
Oral tradition; knowledge gained from traditions, beliefs, experience with nature; passed on from one generation to the next.
Empirical Knowledge:
Knowledge gained through experience; is proven through observations, science and experiments
Scientific Method:
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).
Particle Theory of Matter:
- 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.
Matter:
The “stuff” of the universe; anything that has mass and occupies space (volume)
Property:
A characteristic or quality used to describe matter (ex. Diamonds are shiny)
Qualitative Property:
Properties that can be described using the 5 senses (ex. Sugar tastes sweet).
Quantitative Property:
Properties that involve a measurement (ex. The volume of the liquid is 10).
Physical Property:
Properties that do not involve the formation of a new substance - can be qualitative or quantitative
Chemical Property:
Properties that DO INVOLVE the formation of a new substance: iron reacts with water to form iron oxide (rust)
Physical Change:
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).
Chemical Change:
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
Scientific inquiry is a way of learning which involves:
- Asking questions
- Making observations
- Proposing answers
- Testing those answers
Brittleness:
When subjected to stress, it breaks without significant deformation. Breakability or flexibility. Example: glass is brittle.
Clarity:
The ability to allow light to pass through an object. Opaque - wall, translucent - frosted glass, transparent - water.
Ductility (metals):
Ability to be drawn or pulled into a finer strand ex. Copper can be drawn into thin wires therefore ductile.
Electrical Conductivity:
Ability of a substance to allow electric current to pass through it ex. Copper is a conductor and plastic is not a conductor.
Hardness:
Ability to resist scratch or be scratched by another substance ex. Wax has low hardness, diamonds have high hardness.
Lustre:
Ability to reflect light; shiny or dull
Malleability:
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
Viscosity: (quantitative)
Measure of a fluid’s internal resistance to flow ex. Honey has a high viscosity, water has a low viscosity.
Miscibility:
Ability of two substances to mix together (dissolve into) ex. Water and oil are not miscible.
Odour:
A distinctive smell ex. The odour of an unknown chemical.
Taste:
The sensation of flavour perceived in the mouth and throat on contact with a substance ex. Taste of pizza.
Texture:
The feel, appearance, or consistency of a surface or substance ex. Fuzzy carpet.
Colour:
The way an eye sees the light reflected off an object ex. Green trees (wavelengths of light being reflected).
Mass:
The measure of the amount of matter (kg/g/lbs).
Volume:
The amount of space that a substance or object occupies (m3).
Temperature:
The measure of hotness or coldness (Celsisus or Farenheit).
Boiling Point:
The temperature at which a substance changes state rapidly from a liquid to gas (celsius or fahrenheit). Ex. water becomes vapour.
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).
Melting Point:
The temperature at which a substance changes state from solid to liquid. (celsius or fahrenheit).
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.
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.
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
How does salt melt ice and snow?:
Salt melts ice and snow because it lowers the freezing point of water.
Mass:
The amount of matter in an object. Measured with a scale in g/kg.
Length:
The distance of the longest side of an object. Use a ruler in cm.
Width:
The distance of the shortest side of an object. Use a ruler in cm.
Height:
The distance of the altitude of an object. Use a ruler in cm.
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.
Density:
The mass per unit volume of a substance. Measured in g/mL or g/cm3.
Volume for a regular shaped object:
- Measure length, width, and height
- Calculate V = l x w x h
Volume for a small irregular shaped object:
- Displacement method with graduated cylinder
- Read the meniscus
Volume for a large irregular shaped object:
- Displacement method with overflow can
- Read the meniscus
1cm3 =
1mL
Calculating Slope
Equation:
(mass2 - mass1) / (volume2 - volume1) g/cm3
Slope:
Steeper the slope = greater the density
Grass Method:
Given, Required to Prove (RTP), Analysis, Solve, Statement
Given:
State given info with units of measure.
Required to Prove (RTP):
State what you have to solve for.
Analysis:
Write out the formula you are using.
Solve:
Substitute numbers into formulas to solve unknown (no words).
Statement:
Write a therefore statement.
Density=
Mass/Volume
Volume=
Mass/Density
Mass=
Density x Volum
Physical Property:
Is observed with the senses and can be determined without destroying the object. For example colour, space, mass, length, and odour.
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.
Solid to Liquid:
Liquidification
Liquid to Gas:
Evaporation
Solid to Gas:
Sublimation
Gas to Solid:
Deposition
Gas to Liquid:
Condensation