Physical Science
List of symbols commonly used in chemical equations and give their meanings.
+ means that chemicals are combining, and → means "yields" or "Produces"
Lost the assumptions of the kinetic theory. Explain how the kinetics theory applies to the behavior of gases.
1. All matter is composed of tiny particles 2. These particles are in constant and random motion 3. Particles in a gas collide constantly with each other and the walls of their container- creating pressure 4. As temperature increases it increases the speed of the particles.
Sample question:how many protons, neutrons,and electrons are there in an atom of phosphourus-32
15 protons, 15 electrons, 17 neutrons
Sample question: how many atoms of each type are present in on formula unit of ammonium sulfate(NH4)2SO4?
2 Nitrogen, 8 Hydrogen, 1 sulfur, 4 oxygen
Sample question: A certain radioactive I stop has a half-life of 13 years. How much of 100-g sample would remain after 39 years?
39/13= 3 therefore three half-lives have passed. After 1 half-life 50% will remain, after 2 half-lives 25% will remain, after 3 half-lives 12.5% will remain. So 12.5g remain.
Explain why a catalyst does to a chemical reaction. Explain why an inhibitor does to a chemical reaction.
A catalyst speeds a chemical reaction up. An inhibitor slows a chemical reaction down.
Explain the difference between chemical properties and physical properties
A physical property can be observed without changing the identity of a substance. A chemical property cannot be observed unless the substance reacts with another substance, which would change its identity.
Sample question : explain, of a particle level, why empty aerosol cans should not be thrown into a campfire.
Aerosol cans are full of gas particles in a container with fixed volume. If the can is thrown into a fire, the particles heat up, this causes them to move faster, resulting in more collisions with the walls of their container and therefore more pressure. If there is too much pressure the can will explode, which can be dangerous.
Sample question: classify each of the following reactions as synthesis, decomposition, single replacement, double replacement, or combustion
AgNO3 + NaCl → AgCl + NaNO3- Double Replacement C3H8 + 5O2 → 3CO2 + 4H2O- Combustion N2 + 3H2 → 2NH3 -Synthesis CuCO3 → CuO + CO2- Decomposition 2Fe + 3Cu(NO3)2 → 2Fe(NO3)3 + 3Cu- Single Replacement
List the three kinds of radioactive decay, and differentiate between them in terms of mass, chard , and penetrating power
Alpha decay- During alpha decay an element expels an alpha particle (2 protons and 2 neutrons). This causes a loss of 4amu from the original atom and a decrease of 2 from the atomic number. Alpha particles have very weak penetrating power. Beta Decay- During beta decay a neutron transforms into a proton, beta particle, and antineutrino. The beta particle and antineutrino are expelled from the atom. The penetrating power of a beta particle is weak. This causes no change in the mass of the atom but increases its atomic number by 1. Gamma Decay- releases gamma rays, which have no effect on the atomic number or mass number. Gamma rays are highly energetic electromagnetic waves that have very strong penetrating power.
Describe the structure of an atom
An atom is composed of three major subatomic particles, protons, neutrons, and electrons. Protons and neutrons have roughly the same mass and are found in the center of the atoms in the nucleus. Electrons are much smaller than protons and neutrons and orbit the nucleus in random orbits, but they do have fixed energy.
State Archimedes principle. Give an application.
Archimedes' Principle states the upward buoyant force exerted on object is equal to the weight of the liquid that is displaced. For instance, when a boat is submerged in water, the buoyant force the water exerts on the bottom of the boat is equal to the weight of the water the boat displaces.
Sample question: give the atomic number and mass number for an atom that has 9 protons and 10 neutrons
Atomic number is 9 because that is the number of proton. Mass number is 19 because that is the sum of protons and neutrons.
Sample question: name an element with properties similar to calciums
Be, Mg, Sir, Ba, and Ra are all similar to calcium because they are in the same group
State Bernoullis principle. Give an application
Bernoulli's principle states that the pressure a fluid exerts is inversely proportional to the velocity of the fluid, meaning the faster a fluid is moving the less pressure it exerts. For instance, the water coming out of a shower has a velocity so it means the water exerts less pressure in the shower. This low pressure in the shower causes the shower curtain to move into the shower.
Define binary compound. Recognize binary ionic and binary covalent compounds.
Binary compounds are compounds that are made up of ONLY TWO elements.
State Boyles law in words and mathematically
Boyle's Law states that if temperature is held constant, that pressure of a gas and the volume that gas occupies are indirectly proportional, meaning when pressure increases volume will decrease and when pressure decreases volume will increase
Sample question: what ia the charge of a calcium ion? A bromide ion?
Calcium forms an ion with a charge of +2, Ca+2. Bromine forms an ion with a charge of -1, Br-
Explain how isotopes of carbon in uranium can be used to estimate the ages of all the objects.
Carbon and Uranium have radioactive isotopes that have known half-lives. Based on the amount of parent isotope present, and the amount of daughter nuclei present the exact age of an object can be determined by determining exactly how many half-lives have passed.
Sample question: right formulas for each of the following covlanet( molecular) compounds
Carbon monoxide- CO Dinitrogen pentoxide- N2O5 Sulfur dioxide- SO2 Nitrogen trifluoride- NF3 Silicon dioxide- SiO2
Define cation and anion. Explain how each is formed. Use the periodic table to determine the charge of an ion
Cations are POSITIVELY CHARGED ions. They are formed by the loss of electrons. Anions are NEGATIVELY CHARGED ions. They are formed by gaining electrons.
State Charles law in words and mathematically
Charles' Law states that when pressure is held constant, that volume a gas occupies and the temperature of a gas are directly proportional, meaning when temperature is increased volume will increase and when temperature is decreased volume will decrease as well. V1 over T1 = V2 over T2
Burning oil
Chemical change
Leaves changing color
Chemical change
Reacts with acid
Chemical change
Explain why chemical equations must be balanced and how they are balanced.
Chemical equations must be balanced because mass must be conserved. They're balanced by putting whole number coefficients in front of the chemical symbols.
Give examples of chemical properties and physical properties
Chemical properties- flammability, reacting explosively with water, being highly reactive, being unreactive. Physical properties- malleability, ductility, conductivity, melting point, density, boiling point.
Explain what chemical symbols are and why chemists use them
Chemical symbols are 1, 2, or 3 letter abbreviations of the elements name (sometimes they are abbreviations of the element's Latin name). The first letter is always capitalized and the following letters are always lowercase. They are important because though names can change in different languages, symbols are international.
Fog
Colloid
Gelatin
Colloid
Carbon dioxide
Compound
Iron (lll) chloride
Compound
Explain how the periodic table can be used to determine how many valance electrons an atom has and what energy level the valance electrons are in
Each main group on the periodic table (All of the elements excluding the transition metals) has the same number of valence electrons as the group number. The period that an element is in represents the energy level the valence electrons are in. For example- calcium is in the second group and 4th period, therefore it has 2 valence electrons in the 4th energy level, n=4.
Explain what electron dot diagrams are and how they are constructed
Electron dot diagrams are diagrams in which the elemental symbol is surrounded with somewhere between 1 and 8 dots. Each dot represents a valence electrons of that element.
Gold
Element
Sulfur
Element
Sample question: classify each of the following as a metal, nonmetal, or metalloid
Gold- Metal Sodium- Metal Fluorine- Nonmetal Silicon- Metalloid Krypton- Nonmetal Uranium- Metal
Define heat of fusion, heat of vaporization, melting point, and boiling point.
Heat of Fusion- the amount of ENERGY (kJ) required to melt a substance Heat of Vaporization- the amount of ENERGY (kJ) required to vaporize a substance Melting Point- the TEMPERATURE (K) at which a substance melts, or becomes a liquid Boiling Point- the TEMPERATURE (K) at which a substance boils, or becomes a gas
State the contributions to nuclear chemistry made by Henri Bacquerelcand Marie and Pierre Curie
Henri Becquerel was the first to discover radioactivity but he didn't really understand how it worked. Marie and Pierre Curie studied radioactivity for most of their lives. They discovered 2 new radioactive elements, wrote a paper that is the basis for radiation treatments, and used radon gas to sterilize tissue in WWII
Define heterogeneous mixture , homogeneous mixture(also called solution), compound, element. Understand the difference between colloids and suspensions. Give examples of each type of matter
Heterogeneous mixtures are mixtures that are not uniform, or not even throughout. Homogeneous mixtures are blended evenly throughout. A compound is a pure substance made of atoms chemically bonded together. An element is a purse substance made up of only one type of atom. The particles in a suspension will settle out, particles in a colloid will not settle out.
Organs juice with pulp
Heterogenous mixture
Pond water
Heterogenous mixture
Define hydrate and recognize the formulas of hydrates
Hydrates are compounds that contain a water, this is shown like this CuSO4 · H2O
Sample question: what will happen to the pressure of a gas if it is transferred to a container with a smaller volume.
If a gas is transferred to a container with smaller volume then there will be more collisions between particles and the walls of the container. This will cause pressure to increase. Gay-Lussac's law shows the relationship between volume and pressure to be inversely proportional.
Explain how a nuclear chain reaction works
In a nuclear chain reaction each reaction gives off enough energy to start exactly one more reaction, this means that once the reaction is started it will go to completion unless it is stopped.
Explain the difference between chemical changes and physical changes
In a physical change whatever substance is changed remains the same substance. In a chemical change a new substance is formed
Define isotopes. Explain how the isotopes of an element differ from one another
Isotopes are atoms of a particular element that have differing numbers of neutrons. This also affects the mass of the isotopes and their radioactive stability.
Define mass number and atomic number
Mass number is the sum of protons and neutrons in an atom Atomic number is the number of protons in an atom
List the properties of metals and nonmetals
Metals- are hard, shiny, malleable, ductile, good conductors of heat and electricity, they form cations Non-metals- are brittle, poor conductors of heat and electricity, and they form anions
Explain how most matter responds when heated. Give a notable exception to the general rule.
Most matter expands when heated. The particles gain energy and move slightly away from each other, this is called thermal expansion. Water is a notable exception. Water contracts when heated and expands when cooled.
Sample question : Name each of the following covalent (molecular) compounds
N2O- Dinitrogen Monoxide CO2- Carbon Dioxide SF6- Sulfur Hexafluoride OCl2- Oxygen Dichloride CCl4- Carbon Chloride
Sample question: name each of the following ionic compounds
Na2O- Sodium Oxide FeCl3- Iron (III) Chloride KI- Potassium Iodide NH4Cl- Ammonium Chloride MgSO4- Magnesium Sulfate
Sample question: classify each of the following binary compounds as ionic or covalent
NaCl- Ionic SO2- Covalent N2O4- Covalent BaBr2- Ionic MgO- Ionic PCl3- Covalent
Compare and contrast nuclear fusion and nuclear fission. Give an example or application of each.
Nuclear Fission is the breaking apart of a large atom by firing a neutron into the nucleus of the atom. This releases large amounts of energy and is used in nuclear power plants to create power. Nuclear fusion is the fusion of small atoms into one large one by colliding them at very high speeds. The fusion of hydrogen atoms is the source of the sun's energy.
State Pascals principle. Give an application
Pascal's Principle states that when pressure is applied to a fluid the pressure is distributed evenly throughout the fluid. For instance, when you squeeze the bottom of a tube of toothpaste that pressure is distributed through all the toothpaste and will squeeze out the top.
Give examples of chemical changes and physical changes
Physical Changes- Crumpling up paper, sawing a piece of wood, melting ice, boiling water, dissolving salt in water. In all of these changes the substances do not change their identity. Chemical Changes- A nail rusting, burning gasoline, reacting sodium metal with water. In all of these changes a new substance is formed.
Melting
Physical change
Ripping paper
Physical change
Conductivity
Physical property
Malleability
Physical property
Shape
Physical property
Define plasma
Plasma is a state of matter with very high energy comprised of charged particles. Lightning bolts and the sun are both made up of plasma.
Sample question: right formulas for each of the following ionic compounds
Potassium cyanide- KCN Barium hydroxide- Ba(OH)2 Iron(II) carbonate- FeCO3 Lead(IV) chloride- PbCl4 Copper(II) oxide- CuO
Define quarks.list the subatomic particle that are composed of quarks
Quarks are subatomic particles that make up protons and neutrons.
Give a medical use for radioactive tracers.
Radioactive tracers are radioactive elements that are put into the body because the energy they give off can be "tracked" through the body. This is very useful for MRIs, cat scans, and other imaging techniques in medicine.
Sample question : give me the number of valance electrons for each of the following
Sodium- 1 Fluorine- 7 Silicon- 4 Gallium- 3 Lead- 4 Barium- 2
Sample question : give the energy level in which each elements valance electrons are found
Sodium- 3 Fluorine- 2 Silicon - 3 Gallium- 4 Lead- 6 Barium- 6
Differentiate between solids, liquids, and gases, in terms of shape, volume, spacing between particles, movement of particles, and energy of particles.
Solids have definite shape, definite volume, the particles have very little space between them and are held in fixed positions so they can only vibrate in place. Particles in a solid have the lowest energy of all states of matter. Liquids have indefinite shape but definite volume, the particles have very little space between them but are free to move past each other. Particles in a liquid have more energy than solid but less energy than gasses. Gasses have indefinite shape and indefinite volume, the particles are very far apart and have a lot of space between them. They are free to move about and collide with each other and the walls of their container. Particles in a gas have the highest energy of all states of matter.
Salt water
Solution
Vinegar
Solution
List the types of chemical reactions, give a general equation for each type, and explain how to recognize each.
Synthesis- The combination of two or more reactants to form one product A + B → AB Decomposition- The breakdown of one reactant to form more than one product AB → A + B Single Replacement- One element replaces another in a chemical compound. Remember! Cations replace cations, anions replace anions A + BC → B + AC Double replacement- The swapping of cations or anions in two chemical formulas AB + CD → AD + CB Combustion- Is the burning of a hydrocarbon in the presence of oxygen to create water and carbon dioxide CxHx + O2 → CO2 + H2O
Explain how neutrons are involved in stabilizing the nucleus
The neutrons keep the positively charged protons from repelling each other's. If there are too many or too few neutrons the strong force will not be able to hold the nucleus together and the atom will undergo nuclear decay.
State the octet rule, and explain how it applies to the formation of compounds
The octet rule states that most atoms are most stable when they have a complete octet of electrons in their valence shell. A full octet is comprised of 8 electrons. When compounds form they gain or lose electrons in order to form a full octet.
Name the force that is responsible for holding the nucleus together, and explain how radioactivity is related to the strong force.
The strong force holds the nucleus together. If the nucleus becomes too large (atomic number > 83) or if the ratio of protons: neutrons is unstable the strong force will not be able to hold the nucleus together. This causes it to be radioactive and decay.
Explain what information is given by a chemical formula and why chemical formulas are useful
The subscripts show how many types of each atom are present in the compound.
Explain how a colloid may be distinguished form a solution.
When a light is shined through a solution it will pass straight though. When a light is shined through a colloid the light is visible in the colloid. This is known as the Tyndall Effect.
Sample question: Balance each of the following chemical equations by putting the correct coefficients on the lines
____2Na + _____Cl2 → ____2NaCl _____BaCl2 + _____Na2SO4 → _____BaSO4 + ____2NaCl ____2Al + ____3CuCl2 → ____3Cu + ____2AlCl3 ____2NaClO3 → _____NaCl + ___3O2