C1 + C2 Flashcards
What is the definition of matter?
Substance that occupies space and has mass
What are the three states of matter? What are their distinguishing properties?
Pressure
Volume
Density
Shape
Flow
Solid
Unaffected by change in pressure
Fixed volume
High density
Definite shape
Does not flow
Liquid
Slightly affected by change in pressure
Fixed volume
Moderate-high density
No definitely shape
Flows easily (generally)
Gas
Easily compressed
No fixed volume
Low density
No definitely shape
Flows easily
What are the particle structures of solids, gases and liquids?
Gas
Arranged irregularly
Spread far apart (relatively)
Able to move randomly
Liquid
Closely packed
Irregular arrangement
Able to move past each other
Solid
Pack close together
Regular arrangement
Cannot move freely (only vibrate)
Name the changes in state.
Melting, boiling, evaporation, freezing, condensation
Define atom
The smallest part of an element (element- substance that is made of only one type of atom)
Define molecule
More than 2 atoms
Can be formed by 2 of the same element or 2 different ones
Define Ion.
An atom (or group of atoms) that have a charge as a result of losing or gaining an electron
Cations -> lose electrons -> positive
Anions -> gain ions -> negative
Define melting point (including particle theory and energy change)
When a pure substance turns into a liquid
Endothermic -> particles heat up and move/spread out
Energy change -> absorb energy -> cooler surroundings
Define freezing point (including particle theory)
Liquid cooled down -> freezing point
Exothermic -> particles cool down, move less/ closer together
Energy change -> release energy -> surrounding hotter
Define evaporation (particle theory and energy change)
Liquid is left with surface exposed to air -> evaporation (gas)
Energy change -> absorb energy to become warmer -> cooler surroundings (endothermic)
Particles -> heat and spread
Define boiling (particle theory and energy change)
Gas forms inside a liquid -> boiling
Energy change -> absorb energy and warm -> surroundings are cooler (endothermic)
Particles -> heat and move
Define condensation (particle theory and energy change)
Gas cooled or pressure increased -> condensation (liquid)
Energy change -> release energy become cold -> hotter surroundings (exothermic)
Particles -> cool and move less
Define sublimation (energy change and particle theory)
Some solids do not melt when heated (at normal pressure) instead goes directly into gas -> sublimation (Called the same thing when the other way around)
Energy change -> releases or absorbs (direction of reaction)
Particles -> cool down or heat up (depends on direction of reaction)
What the boiling point and freezing point of water (°C)? How can this be converted into Kelvin scale?
Boiling -> 100°
Freezing -> 0°
Kelvin -> add 273 to Celsius
Define particles. How does kinetic energy effect the particles?
All substances are made of particles
Particles move -> kinetic energy
More heat -> more kinetic energy
Define diffusion
The net movement of particles from a region of high concentration to a region of low concentration down a concentration gradient, as a result of their random movement
Passive process
Diffuse until equilibrium
What are some factors that effect diffusion?
Distance to travel, temp, concentration, state of matter (slow/nonexistent in solids, increased in liquids, fast in gases) , size of particles/molecules (slower diffusion)
What is the cause of pressure?
Particles of gas colliding with the sides of the container, exerting force and keeping it expanded
Size of container and concentration of particles -> change pressure
How are intervals of time measured?
Stopwatch
How is temperature measured?
Thermometer
How is mass measured?
Balances
How are volumes and liquids measured?
Pipette (small amount)
-> digital pipette for extra precision
Burette
Volumetric flask
Gas syringe
Measuring cylinder
What are the criteria of a pure substance?
It contains only one substance, containing no impurities
-> definite melting and boiling points
Ex: elements and compounds
Define mixture
Impure -> contain more than two elements/compounds that aren’t chemically bonded
Connection between pure substances and rising temps when melting
When a pure substance melts, the temperature will stop rising
-> because it is an endothermic process
(Unlike wax -> impure -> melts over a range of temps)
What is paper chromatography?
Used to separate mixture of soluble substances by running a solvent through the mixture, causing the substances to move (they move at different rates)
Stationary phase -> paper
Mobile phase-> solvent
NEED TO BE SOLUBLE
What is the Rf value?
The ratio of the distanced moved (from the origin)
What is the equation of Rf value?
Rf=distance moved by substance/distance moved by solvent (solvent front)
Solvent always travel farther -> Rf<1
What is ‘unique’ about pure compounds in chromatographs?
Pure compounds only produce one spot in ALL solvents
Why is purity important in everyday life?
Medicinal drugs -> as pure as possible -> contamination could lead to harmful side effects
Colored dyes -> highly regulated -> many have harmful side effects
What is ‘unique’ about the melting and boiling points of mixtures?
Each part of mixture boil at different temperatures and will melt/boil over a range of temps
How can boiling and melting points be used to determine purity?
If the substance is pure the temp of the substance will stop increasing while boiling/melting -> definitive melting and boiling point
How can different mixtures be separated?
Solid + solid (powder)
Suspension of solid in liquid
Liquid + liquid (not homogenous)
Solution of solid in liquid
Two or more liquids mixed together
Solution of two+ solids in liquids
Solid + solid (powder)
-> difference in property (magnetism, solubility, sublimation, density)
Suspension of solid in liquid
-> filtration or centrifugation
Liquid + liquid (not homogenous)
-> separating funnel or decantation
Solution of solid in liquid
->crystallization (for solid)
->distillation (liquid)
Two or more liquids mixed together
-> fractional distillation
Solution of two+ solids in liquids
-> chromatography
Explain solubility (as a method of seperation)
Add mixture of solids to a solvent -> only one is soluble in
Pour liquid out (decant)
Repeat until solid is obtained
Explain filtration
Solid material is collected in filter paper -> liquid passes through
Explain centrifugation
Spin sample of solution very quickly -> solid goes to bottom because of higher density -> liquid decanted
Explain crystallization
Solvent evaporated, leaving behind solute -> cools -> crystals
Explain distillation
Separation of solute and solvent -> solvent evaporates at boiling point -> travels down condescending tube (tube surrounded by cool water) -> comes out as pure substance
Explain fractional distillation
Separation by boiling point -> volatile liquids (evaporates at normal temps) travel up fractional column as well as water vapor -> volatile liquid vapor passes to the condenser (temp in column is above boiling point) -> water vapor condenses in the column (glass rods (more surface area) and cooler at top) -> flows back into flask
Define solution
Made of a solvent (the liquid which it dissolves in) and solute (solid which dissolves)
Define a concentrated and dilute solution
Concentrated-High proportion of solute
Dilute-low proportion of solute
Define saturated solution
No more solid can be dissolved at this temperature
Define solubility
The ability of a solute to dissolve in a solvent
Define compound
More than 2 elements/compounds that are chemically combined
