Matter, Phases of Matter and Kinetic and Molecular Theory Flashcards
What is matter?
Matter is defined as anything that occupies space and has mass
What determines the observable characteristics of matter and the way that it reacts?
The properties of its particles
What are twelve properties of matter?
Strength Brittle Malleable Ductile Thermal conductivity Electrical conductivity Lustre Magnetic Density Sonorous Melting point Boiling point
What does the property of strength indicate?
How difficult or easy it is to break the material
What does the property of brittleness indicate?
The material breaks easily
What does the property of malleability indicate?
The material can be bent and made into sheets
What does the property of ductility indicate?
The material can be drawn into wire
What does the property of thermal conductivity indicate?
The material can conduct heat
What does the property of electrical conductivity indicate?
The material can conduct electricity
What does the property of lustre indicate?
The shine that a material has
What does the property of magnetism indicate?
The material can be attracted by a magnet
What does the property of density indicate?
The mass of the material per unit volume
What does the property of sonorousity indicate?
The material emits a ringing sound when struck
What does the property of melting point indicate?
The temperature at which the material changes from a solid to a liquid
What does the property of boiling point indicate?
The temperature at which the material changes from a liquid to a gas
How are materials classified?
Into pure and impure substances
How are pure substances classified?
Into elements and compounds
How are impure substances classified?
Into homogenous and heterogeneous mixtures
How are elements classified?
Into metals and non-metals
What are pure substances?
Substances that only have one type of molecule in them
They have a constant composition
What do pure substances have?
A constant composition
What is an element?
A substance which cannot be broken down into further simpler substances
Who created the Periodic Table?
Dmitri Mendelev
What is the Periodic Table?
An arrangement of all the elements in a tabulated form
What are the horizontal rows of the Periodic Table called?
Periods
What are the vertical columns in the Periodic Table called?
Groups
Where are metals found on the Periodic Table?
Mainly on the left hand side
What are the metals in group one called?
Alkali metals
What are the metals in group two in the Periodic Table called?
Alkaline earth metals
Where are the non-metals on the Periodic Table found?
Mainly on the right hand side
What are the elements in group seventeen called?
The halogens
What are the elements in group eighteen called?
The noble gases
What are the properties of metals?
Have lustre Are malleable Are ductile Are sonorous Are heat conductors Are electrical conductors
What are the properties of non-metals?
Are dull Are brittle Are not sonorous Are heat insulators Are electrical insulators
What are electrical cables generally made of?
Copper
Why is copper used for electrical cables?
It is a very good electrical conductor
What usually surrounds copper cable?
Plastic
Why does plastic often surround electrical cables?
It is a good electrical insulator
Why is nichrome used for heater and stove elements?
It conducts electricity well, but has high resistance and therefore creates heat
Is air a conductor or insulator?
It is a thermal insulator
What three elements are magnetic?
Nickel
Cobalt
Iron
What are metalloids?
Elements that can be classified as either metals or non-metals
Where can metalloids be found?
Along the metal non-metal division line
Why can metalloids be classified either way?
They display properties of both metals and non metals
What are the eight metalloids?
Boron Silicon Germanium Arsenic Antimony Tellurium Polonium Astatine
What property do metalloids have that metals do not?
They conduct electricity better at high temperatures
What two metalloids are commonly found in microchips?
Silicon
Germanium
What is a compound?
Two or more elements chemically combined in a fixed ratio
What is another term for an impure substance?
A mixture
What is a mixture?
A combination of two or more substances in which the substances retain their own properties (no chemical change)
The substances can be present in any ratio
What are the two types of mixtures?
Homogeneous
Heterogenous
What is a homogeneous mixture?
A mixture in which the composition of the mixture is the same throughout
It consists of two or more substances in the same phase
How can one tell if something is a homogeneous mixture?
No amount of optical magnification will reveal one region to be different from another
What is a heterogenous mixture?
A mixture in which the composition is not uniform
What is a suspension?
A heterogeneous mixture where the solute is not dissolved in the solvent, but merely dispersed through it
Give an example of a suspension
Sand mixed in water
If left to sand, the sand will settle to the bottom
What is immiscible?
The term used to describe two liquids that do not mix
What is an emulsion?
A heterogenous mixture made of two or more immiscible liquids
Once again the particles are not dissolved into one another, merely dispersed
How can mixtures be separated?
By physical means
What are some examples of physical separation methods?
Evaporation Condensation Funnelling Magnetism Filtration
What two methods can be used to check the purity of a substance?
Boiling / melting
Chromatography
How does boiling test for purity?
Different substances have different boiling points
If the substance boils at two or more points, then the substance is not pure
How does chromatography test for purity?
Different substances move through filters at different rates
If the substance is passed through water, then the different components of the mixture could become visible
What five properties are used to compare solids liquids and gases?
Intermolecular forces (IMF) Movement Shape Volume Compressibility
What are the IMF like in a solid?
Strong
They hold particles in a fixed formation called a crystal lattice
What is the movement like in a solid?
The particles vibrate in fixed positions
How does matter exist?
In phases
What is the shape of a solid like?
It holds its own shape
What is the volume of a solid like?
It has its own volume
Can a solid be compressed?
No
It’s particles are too close together
What are the IMF like in a liquid?
Weaker
Can still hold particles together
What is the movement of a liquid like?
The particles can roll over each other and change places
They can be poured
What is the shape of a liquid like?
It takes on the shape of the container
What is the volume of a liquid like?
It has its own volume
Can you compress a liquid?
No
The particles are still too close together
What are the IMF in a gas like?
Almost non-existent
What is the movement of a gas like?
Particles are free to move and have lots of kinetic energy
What is the shape of a gas like?
Has no shape
What is the volume of a gas like?
Does not have its own volume
Takes on volume of the container
Are gases compressible?
Yes
The particles are far apart
What is temperature?
A measure of the average kinetic energy of particles
The velocity at which particles move
What is important to note about molecules and their movement?
All particles move, but not all at the same speed
What is the formula for kinetic energy?
Ek = 1/2 mv^s
Kinetic energy is equal to half of mass times velocity squared
When do substances change phase?
When their temperature changes past a certain point
What is a melting point?
The point at which a solid changes to a liquid
What is the freezing point?
The point at which a liquid changes to a solid
What is interesting about the freezing and melting point of a substance?
They are the same temperature
What is the boiling point?
The point at which a liquid changes to a gas and vice versa
What is the difference between boiling and evaporation?
Boiling: all of the molecules increase in temperature at the same rate and they will all turn into a gas. Boiling only occurs at specific temperatures
Evaporation: only the molecules near the surface of a liquid turn into a liquid and the substance does not heat up evenly. Evaporation can happen at any temperature
Why is evaporation important for maintaining body temperature?
When molecules evaporate, they take their increased energy with them
The rest of the substance therefore has less average energy i.e is colder
When sweat evaporates from our skin, our skin gets colder
When does boiling occur?
When vapour pressure and atmospheric pressure are equal
What can change the boiling point of a substance?
Atmospheric pressure
Why does atmospheric pressure affect the boiling point of a substance?
More energy is needed to overcome greater atmospheric pressure
What kind of relationship exists between altitude and the boiling point of a substance?
Inverse
The greater the altitude, the lower the boiling point
What is sublimation?
When a substance changes straight from a solid to a gas
Give an example of a substance that sublimates
Iodine
Why does sublimation occur?
The IMF are so weak that only a little bit of heat is needed to break them
What kind of change is a phase change?
Physical
How does the temperature of a solid rise?
More energy is added
They vibrate faster
Why do molecules have potential energy?
They have forces of attraction and repulsion between them
What happens to a substance when it reaches its melting point?
The particles’ kinetic energy remains constant and their potential energy is increased
When can a substance’s temperature begin to rise (after a phase change)?
Only when all the molecules have changed phase
What happens when a liquid reaches its boiling point?
The kinetic energy stops increasing, instead the potential energy increases
Which takes longer-boiling or melting?
Boiling
Why does boiling take longer than melting?
In boiling, the particles have to completely break the forces of attraction between them, rather than just the crystal lattice structure
What is the transition phase in a heating curve?
The time when the kinetic energy of particles increases or decreases
What is a heating curve?
A graph showing the phase change of a substance
