Test 2- Phase change and Matter Flashcards
Solid
Doesn’t take shape of the container, definite volume, vibrational energy, lowest kinetic energy, no change in volume due to pressure.
Liquid
Takes shape of container, definite volume, vibrational and rotational energy, no change in volume due to pressure.
Gas
Takes shape of container, no definite volume, vibrational and rotational and translational energy, highest kinetic energy, pressure can be applied and volume will change.
Plasma
Just like gas except its composed of ions and electrons.
Both Liquids and gases are considered
Fluids
Phases at atomic level
Endothermic
Energy going in/being absorbed
Exothermic
Energy coming out/being released
Endothermic examples
Sweating (energy going into sweat from your body in order to evaporate), Panting dogs (same as sweating since panting is the equivalent of sweating for dogs), chills when its 100 degrees and you get out of the pool (energy is being absorbed by the water from your body to evaporate)
Exothermic Examples
Making ice cubes (energy is being released in order to solidify)
Phase changes
•S > L - Melting - endothermic •L > S - Freezing - Exothermic •L > G - Evaporating or boiling - Endothermic •G > L - Condensing - Exothermic •S > G - Sublimation - Endothermic
Phase change diagram
Heat of Fusion
The energy needed in joules to change one gram of substance from S>L or L>S
Chemical energy is called
Entropy
Energy is measured in
Joules
Cp
specific heat: Amount of energy needed in joules to raise on gram of substance by one Kelvin J/g degree Celsius or J/g degree Kelvin
Graph down vs. Graph up
•Down graph: energy released •Up Graph: Energy put in
KE vs. PE
•KE increases as temperature increases (lines going up/down) •PE energy increases during phase change (straight line)
Why is steam burn worse than hot water burn?
Hot water only transfers the energy it needs to evaporate while steam first needs to condense, then evaporate.
S>L vs. L>G
•S>L 334 J/g needs to overcome interatomic molecules •L>G 2260 J/g needs to overcome intermolecular and air pressure •More energy needed to go from L>G because of bonds and the air pressure acts as “bouncers” pushing the escaped liquid molecules back
Second law of thermodynamics
Describes direction of heat flow. Heat flows from a hotter object to a cooler one. Entropy of a system and its surroundings increase. Entropy is the fact that everything is moving towards disorganization.
Temperature _____ as water freezes
remains the same
Freezing point is the same as
melting point
Boiling point is the same as
condensing point
Water can exist as a ____ at zero degrees Celsius
liquid or a solid
Kinetic energy ______ during phase change
Remains the same
It will take ______ to cook an egg at lower pressure
more time
Temperature of boiling water in Death valley is _____
higher
KE=
KE= Average temperature. Doesn’t increase during phase change because temperature remains the same.
Pipes burst in the winter because __________
water expands as it freezes
Spaghetti takes longer to cook in the mountains because
the boiling temperature in higher altitudes is lower than at sea level so the pasta takes longer to cook. This is because there is less air pressure acting as bouncers, pushing the water back (air pressure).
Water freezes and ice melts at 0°C since
freezing point and melting point are the same
Water boils at
100dC
Ice is warmed to the melting point-
The frozen/solid molecules vibrate increasingly until they break apart. 0°C
Water is warmed to the boiling point-
Liquid molecules move faster and faster until they break apart. 100°C
Water is cooled to the freezing point-
Liquid molecules move slower and slower until they begin to stick together. 0°C
Lower air pressure, increased altitude will
not affect freezing point and melting point and decrease boiling point.
In a pressure cooker, the increased air pressure will
create a higher boiling point, making the food cook faster.
Drinking bird
The water is absorbed by the bird’s head, making it heavier which causes it to tip over because of gravity. The water evaporates off the head, cooling the temperature and causing the fluid to condense and the pressure to decrease. The water is forced to the tip of the bird. The vapor goes pack up and the bird becomes upright. Vapor travels from them bottom to the top until the pressure in both spheres equalize and the bird begins the process over again.
Miracle thaw does not possess amazing properties.
It is simply a slab of black aluminum with grooves. Aluminum is a good conductor, but not a superconductor. Also, their marketing principle that heat is transferred to the frozen food is simply a restatement of the second law of thermodynamics.
The size affects the heat flow because
it is fairly big and the bigger it is, the more heat is can absorb as evident by the equation Q=mΔTCp
Grooves act as a
water channel for the cold water, which would slow down the melting process.
Calometer lab- energy flow
The kinetic energy from striking the match it turned into chemical energy in the match and light and thermal energy. Then the energy transferred into the food and turned from chemical to thermal/light energy as it burned. It transferred into the water as thermal energy, which increased the movement of the molecules (temp) and kinetic energy.
Not all energy released
was accounted for
The law of the conservation of energy relates to this activity because
the law of conservation states that energy cannot be created or destroyed, but it can change form. In this activity, energy is not being created to heat the water; the energy is changing from its chemical form in the food to thermal energy, heating the water.
Nutritional Calorie vs. Calorie
A Nutritional Calorie is the amount of energy needed to raise the temperature of one kilogram of water by one degree Celsius. It is also the type of calorie you find in your food. A calorie is the amount of energy needed to raise one gram of water by one degree Celsius. One food Calorie=1000 calories.
Q=mHf or Q=mHv is used to
calculate energy during phase change (straight line)
Q= mΔTCp is used to
calculate the energy needed to raise/lower the temperature of a substance.
mΔTCp=mΔTCp
to calculate final temp or other variables
Specific heat of water:
4.184 J/g°C
If something has a smaller mass,
it won’t get as hot. So, if you put a piece of pizza on aluminum foil and put it in the oven to heat it, it wont get too hot since the mass of the foil is really small.
Classifying Matter chart
Pure
•Uniform throughout •Can NOT be separated easily by ordinary physical means like separating m&m or Italian dressing, straining, filtering, or distilling •Distillation uses differences in boiling points (ex. Fractional)
Element
•Atoms are the smallest piece of an element •Cant be separated by physical or chemical means easily at all
Compound
•Elements turn into compounds through chemical change •Different from the elements that make up them •Unique/different properties both physical and chemical properties
Molecular
•2 or more non metals •Share electrons •Molecules-smallest piece •Not attached •Ex. Water
Ionic
•Metals and nonmetals •Transfer electrons •Big cluster- all attached •Crystal lattice structure/Ionic lattice (cluster of Na+Cl and –Cl) •Written in the simplest ratio formula unit (fu) •Chromatography?
Mixture
•Two or more substances •Each retains its chemical properties
Homogeneous
•Solution •Very small particles that are equally/evenly distributed •Ex. Coolaid •2 parts to a solution- Solvent and solute •Solvent- bigger part that does the dissolving •Solute- smaller part that gets dissolved •Soda is a solution when flat •Doesn’t have to be a solid and liquid- can be any phase. Ex. Alloy- 2 metals- pewter, brass, and bronze
Heterogeneous
Particles are not small enough to the point where they are invisible/solution is clear
Colloid or Colloid Dispersions
•Some medium sizes particles- light bounces or is bent when it hits the particles- the creates color •Ex. Mayonnaise- oil, vinegar, and egg clear, mixture becomes white. •Dispersed phase- smaller part •Despersed medium- Larger part
L + L Colloid
Emulsion- mayo
S + L Colloid
Sol- Blood
S + G Colloid
Aerosol- Smoke
L + S Colloid
Gel- Jelly
L + G Colloid
Liquid aerosol- Cloud, fog
G + L Colloid
Foam- shaving cream
Suspension
•Even larger particles that can be seen with the naked eye •Many times, particles are so large, they settle with gravity •Ex. Italian dressing, OJ with pulp, sand in water •Easy to separate
Characteristics of a mixture:
2+ elements are combines with one another and elements in a mixture are combined with out creating a mixture. A CHEMICAL CHANGE DOES NOT OCCURE WITHIN A MIXTURE
The 3 main types of mixtures are:
solution, colloid, and suspension
In a solution, particels are
too small to see
You unmix things chemically by
breaking some bonds
Mixtures that you can break down physically include
mud, trail mix, and salad
Many larger complex molecules are
just smaller molecules bonded together like building blocks
The starch molecule is
Amylose
Humans cant use the large molecules in proteins but can use
the amino acids that make up the proteins
Atoms are the
building blocks of building blocks
the atoms that repeatedly show up in macaroni salad.
CHONPS
How are all things related?
All things are made up of molecules and molecules are made of the same atoms, just arranged in different ways.
Examples of Solution, colloid, and Suspension-
Vinegar, mayonnaise, and mustard
The difference between an element and an atom is that
an atom is the smallest piece of an element and elements are made of atoms.
The difference between a compound and a molecule is that
a molecule is the smallest piece of a molecular compound while a compound is a pure structure composed of two or more separated elements.
The difference between an element and a compound is that
an element is made of one type of atom but a compound is made of two or more types of atoms
The difference between an atom and a molecule is that
an atom is the smallest piece of an element and a molecule is the smallest piece of a molecular compound.
The difference between a mixture and a pure substance is that
a mixture can be easily separated by ordinary means such as straining, filtering, distilling and pure substances cant.
The purpose of the water is to
act as a solvent to break apart the mixture of the ink and carry the ink up the paper.
Permanent markers would not work because
they are not soluble in liquid
Color separates and appears at different positions because
they travel at different rates because they are not all equally soluble and less soluble components will move at slower rates and more soluble components will move at faster rates.
Absorbent:
A substance that the mixture binds to.
Eluent:
A solvent specific to chromatography that does the dissolving.
Solvent:
In a solution, the substance in which the solute dissolves
Chromatography:
Analytical method used in lab to separate a mixture based on the components moving at different rates.
Retention factor:
A calculation that compares the distance traveled by an ion in solution to the distance traveled by the solvent.
Chemical change
changes the chemical state of something and cannot be easily separated. Drastic color change is an indication. Ex. Burning
Physical change
changes can be easily separated and does not change the chemical state of something. Ex. Dissolving, cutting hair, density
Laser disk clips
•Oxygen in a balloon will not explode. Oxygen doesn’t burn, only helps things burn •Thermite reaction makes molten iron •Hydrogen explodes and oxygen helps things explode •Hydrogen is twice as buoyant as helium but is reactive •Hydrogen and oxygen make the biggest explosion
• 7 diatonic elements:
Br, I, N, Cl, H, O, F- needs to bond
Break bond vs. bonds formed
•Bonds broken- energy absorbed- endothermic process •Bonds formed- energy released- exothermic process
Calorie vs. calorie vs. joule
1 Calorie=1000 calories
1 joule= 1 calorie
Energy vs. Work vs. joule
Energy: the ability to do work
Work: exerting energy
Joule: what energy is measured in
