Semester 1 Final Review Flashcards
What is a chemical property?
The ability or inability of a substance to combine with or change into one or more other substances.
What is a physical property?
A characteristic of matter that can be observed or measured without changing the sample’s composition
What are some physical properties?
Density, color, odor, hardness, melting point, and boiling point are common physical properties
What can physical properties be further described as?
Intensive or extensive properties
How many significant figures are there in a distance measurement of 180,200.06 cm?
8
What are the SI base units?
Seconds, meters, kilograms, kelvins, moles, ampere, candela
In addition and subtraction, the answer must not have more significant figures…
To the right of the decimal point
Accuracy pertains to?
Closeness of a measurement to an accepted value
What does precision pertain to?
Precision is the sameness of measurements that show little to no variation
What is a solution?
A homogeneous mixture
What is the law of conservation of mass?
Law that states that mass in neither created nor destroyed in a chemical reaction
What is the periodic table?
The grid organizing elements into periods and groups
What is percent by mass?
The ratio of the mass of each element to the total mass of the compound
What is the definition regarding the states of matter?
Three physical forms that describe the matter that exists on Earth
What is crystallization?
A separation technique that results in the formation of pure solid particles from a solution
What is chromatography?
A technique that separates that components of a mixture
What is the definition of a liquid?
A form of matter with a constant volume that takes the shape of its container
What is the definition of a solid?
A form of matter with a definite shape and volume
What are some chemical properties?
Forms with elements exposed to air, reactivity with another substance, ability to combine with another substance
What are some intensive physical properties?
Chemical formula CO, colorless, solid at room temperature, melting point, conducts electricity, density
What are some extensive physical properties?
Mass
What words indicate a physical change?
Boiling, freezing, condense, crush, vaporize
What words indicate a chemical change?
Explode, tarnish, ferment, burn, corrode
What mixtures can be identified as homogeneous?
Saline, sterling silver (silver & copper mix), black tea
What mixtures can be identified as heterogeneous?
Glass of soda, bowl of cereal, sidewalk pavement, sand, salad, mulch, chocolate chip cookies
Identify the technique you would use to separate two substances with different boiling points
Distillation or chromatography is the technique you would use to separate two substances with different boiling points
What is the law that states that mass cannot be created nor destroyed in ordinary chemical and physical changes?
The law of conservation of mass
What is the charge of a proton?
Positive
Where is the proton found?
Nucleus
What is the law of conservation of mass?
Law that states that mass cannot be created nor destroyed in ordinary chemical and physical changes
What is the charge of the electron?
Negative
Where is the electron found?
Located outside surrounding the nucleus on the electron cloud
What is the law of multiple proportions?
When two elements combine to form two or more compounds, the mass of one element that combines with a given mass of the other element is in the ratio of the small whole numbers
What is the charge of a neutron?
Neutral/no electrical charge
Where is the neutron found?
Located inside the nucleus
What is the law that states when two elements combine to form two or more compounds, the mass of one element that combines with a given mass of the other element is in the ratio of the small whole numbers?
The law of multiple proportions
What contributions did Aristotle make to atomic theory?
Halted any progression in atomic theory. Believed that matter existed of only 4 elements
What contributions did Democritus make to atomic theory?
Believed that atoms were the building blocks of matter and atoms were indivisible
What contributions did Dalton make to atomic theory?
Determined that atoms could combine to form compounds
What contributions did Thomson make to atomic theory?
Used the cathode ray tubes to discover the electron
What contributions did Rutherford make to atomic theory?
Used the gold foil experiment to discover the nucleus of the atom
What contributions did Bohr make to atomic theory?
Determined that electrons exist in energy levels at certain distance from the nucleus
What contributions did Newlands make to atomic theory?
Developed the law of octaves
What contributions did Moseley make to atomic theory?
Arranged the elements by increasing atomic number
What contributions did Mendeleev make to atomic theory?
Developed the first widely accepted periodic table of elements by arranging the elements by increasing atomic mass.
Why was Mendeleev’s periodic table widely accepted?
He predicted the existence and properties of undiscovered elements. As well, he was the first to notice a pattern of similar properties among elements
How do you know which elements have the same or similar chemical properties?
If they are in the same group
What is an element with chemical properties similar to Iodine?
Chlorine
What is an element with chemical properties similar to Iron?
Ruthantum
What is the group name of group 1?
Alkali metals
What is the group name of group 17?
Halogens
What is the group name of group 2?
Alkali earth metals
What is the group name of group 18?
Noble gases
What is the group name of groups 3-12?
Transition metals
What is the group name of groups 14-18?
Nonmetals
What is the group name of “stair step” between groups 13-16?
Metalloids
What is the group name of the groups to the left of metalloids?
Other metals
What do the lewis dot diagrams show?
The valence electrons
What is a extensive property?
Properties that depend on the amount of a substance present (mass, length, volume)
What is an intensive property?
Properties that are independent on the amount of substance present (density)
Can the inability of a substance to change into another substance be considered a chemical property?
Yes
What is a phase change?
A transition of matter from one state to another
How do you know a chemical change has occurred? Give evidence.
The observation that the product has different properties than the reactants is evidence that a chemical reaction has taken place because they always produce a change in properties
What is the definition of mass?
A measurement that reflects the amount of matter
What is the definition of weight?
A measurement of the amount of matter and the Earth’s gravitational pull on that matter
What is the definition of volume?
The space occupied by an object
What is the definition of density?
A physical property of matter defined as the amount of mass per unit volume
What is the definition of an atom?
The smallest particle of matter that retains the properties of the element
What is the definition of a molecule?
A group of atoms
What is the definition of a pure substance?
Matter with a uniform and unchanging composition
What is the definition of a heterogeneous mixture?
A mixture that does not blend smoothly throughout and in which the individual substances remain distinct
What is the definition of a homogeneous mixture?
A mixture that has constant composition throughout; it always has a single phase
What is a theory?
An explanation of a natural phenomenon based on many observations and investigations over time
What is scientific law?
A relationship in nature that is supported by many experiments
What is pure research?
Research for the sake of knowledge
What is applied research?
Research to solve a specific problem
What is a substance?
Matter that has a definite and uniform composition (a.k.a a chemical)
What is the SI base unit of time?
Seconds
What is the SI base unit of length?
Meters
What is the SI base unit of mass?
Kilograms
What is the SI base unit of temperature?
Kelvins
What is the SI base unit of amount of a substance?
Moles
What is the SI base unit of an electric current?
Ampere
What is the SI base unit of luminous intensity?
Candela
What is base unit?
A defined unit in a system of measurement that is based on an object or event in the physical world
What is a derived unit?
A unit that is defined by a combination of base units
What is dimensional analysis?
A systematic approach to problem solving that used conversion factors to convert from one unit to another
What is a conversion factor?
A ratio of equivalent values having different units
What must a conversion factor in dimensional analysis accomplish?
Must cancel one unit and introduce a new one
What is error?
The difference between an experimental value and an accepted value
What is the percent error equation?
%Error= |experimental value- accepted value|/ accepted value x 100
What is percent error?
Expresses error as a percentage of the accepted value
What are significant figures?
The reported digits indicated from the precision of a measurement
What are the rules of significant figures?
Nonzero numbers are always significant.
All final zeroes to the right of the decimal are significant.
Any zero between significant figures is significant.
Placeholder zeroes are not significant. To remove placeholder zeros, rewrite the number in scientific notation
Counting numbers and defined constants have an infinite number of significant figures
What is the rule of significant figures for addition and subtraction?
Answer must have the same number of digits to the right of the decimal as the original value with the fewest number of digits
What is the rule of significant figures for multiplication and division?
Answer must have the same number of significant figures as the value with the fewest significant figures
What does endothermic mean?
Absorbs or uses heat energy
What does exothermic mean?
Releases heat energy
What is an independent variable?
Variable that scientists deliberately change during an experiment
What is a dependent variable?
Variable whose value depends on or changes in response to the independent variable
What does gas refer to?
A substance that is naturally in the gaseous state at room temperature
What does vapor refer to?
The gaseous state of a substance that is a solid or a liquid at room temperatures
True or False: A substance can often be identified by its intensive properties
True
What is a physical change?
A change which alters a substance without changing its composition
What is a chemical change?
A process that involves one or more substances changing into new substances
What terms generally refer to chemical reactions?
Decompose, explode, rust, oxidize, corrode, tarnish, ferment, burn, or rot
The starting substances in a chemical reaction are called what?
Reactants
The new substances formed in a chemical reaction are called what?
Products
True or False: A chemical reaction always produces a change in properties?
true
What is the equation form of the law of conservation of mass?
Mass reactants = mass products
What is an element?
A pure substance that cannot be separated into simpler substances by physical or chemical means
Why is the periodic table called periodic?
The pattern of similar properties repeats from period to period
True or False: Elements in the same group have similar chemical and physical properties.
True
What is a compound?
Made up of two or more different elements that are combined chemically in a fixed ratio
What is the percent by mass ratio?
Ratio of mass of each element to the total mass of the compound expressed as a percentage
What is the percent by mass equation?
mass of element/mass of compound x 100
What is a mixture?
A combination of two or more pure substances in which each pure substance retains its individual chemical properties
True or False: Homogeneous mixtures are also referred to as solutions
True
What is an alloy?
A homogeneous mixture of metals
True or False: heterogeneous mixtures composed of solids and liquids are easily separated by filtration
True
What is filtration?
A technique that uses a porous barrier to separate a solid from a liquid
True or False: Many homogeneous mixtures can be separated by distillation
True
What is distillation?
A physical separation technique that is based on differences in the boiling points of the substances involved
What is sublimation?
The process during which a solid changes to vapor without melting without going through the liquid phase
True or False: Sublimation can be used to separate two solids present in a mixture when one of the solids sublimates but not the other
True
What is an atom?
Smallest particle of matter that retains the properties of the element
Protons and neutrons have their own structures and are composed of subatomic particles called what?
Quarks
What is the atomic number?
Refers to the number of protons in an atom
True or False: All atoms of an element have the same number of protons and electrons, but the number of neutrons might differ.
True
What is the mass number?
the sum of the atomic number (number of protons) and neutrons in the nucleus
How do you write isotopes in isotope notation?
Write the element symbol, top number is the mass number (the number that should be different), bottom number is the atomic number (number that should always stay the same)
True or False: Each element’s atomic emission spectrum is unique and can be used to identify an element
True
What is the ground state?
Lowest allowable energy state of an atom, atoms normally exist with electrons at the lowest possible energy levels closest to the nucleus
Is it true that when an atom gains energy, it is said to be in an excited state?
Yes
What is the principal quantum number?
N
What does the quantum number n indicate?
The energy level
What is electron configuration?
The arrangement of electrons in an atom
What does the aufbau principle state?
Electrons fill orbitals with the lowest energy first
What does the Pauli Exclusion Principle state?
Only 2 electrons can be in the same orbital at a time
What is Hund’s Rule?
Electrons will fill all the orbitals with the same energy level and quantum numbers singly before pairing begins
What did DeBrogli propose?
Electrons act like waves in a confined space
What is a valence electron?
Electrons in the atom’s outermost orbitals
What is the law of conservation of energy?
Energy can neither be created nor destroyed only converted from one form of energy to another
What is an isotope?
Same number of protons but different number of neutrons
What does the mass number equal?
Equals the total number of protons and neutrons
What are the names of the electron orbital shapes?
S, p, d, f
How many orbitals and electrons does the s-orbital have? What’s its spherical shape?
1 orbital, 2 electrons max, spherical shape
How many orbitals and electrons does the p-orbital have? What’s its spherical shape?
3 orbitals, 6 electrons max, dumbbell shape
How many orbitals and electrons does the d-orbital have? What’s its spherical shape?
5 orbitals, 10 electrons max, clover shape & 1 donut shape
How many orbitals and electrons does the f-orbital have? What’s its spherical shape?
7 orbitals, 14 electrons max, double dumbbell shape
What is a period?
A horizontal row of elements in the periodic table that has increasing atomic number
What is a group?
A vertical column of elements in the periodic table
What is electron shielding?
Inner electrons shield outer electrons from the nucleus
How is the periodic table organized?
The periodic table is organized left-to-right and top-to-bottom by increasing atomic number. This pattern of order with the periodic table is called periodicity.
What are the general properties for the alkali metals?
Extremely reactive, reacts with water, very soft, easily cut, good conductor of electricity
What are the general properties for alkali earth metals?
Highly reactive (not as much as group 1), reacts with oxygen in the air, higher melting points that the alkali metals
What are the general properties for transition metals?
Less reactive than alkali metals and alkali earth metals, most are solid at room temperature (Hg is a liquid), good conductors of heat and electricity
What are the general properties for halogens?
Most reactive group of nonmetals, reacts to form salts, likely to react with alkali metals, found in sea water and within Earth’s crust, all are liquids at room temperature (except Bromine), can be poisonous when they are not combined as compounds
What are the general properties for noble gases?
Very unreactive due to stable electron configurations, only Kr, Xe, & Rn have been able to form compounds, colorless, odorless, tasteless
What are the general properties for metals?
Some can react to form poisons, good conductors of heat and electricity, silver/grey in color, malleable
What are the general properties for non-metals?
Easily gains electrons, exists at room temperature as a gas or a solid, poor conductors of heat and electricity
What are the general properties for semiconductors (metalloids)?
Shares properties of metals and nonmetals, not typically reactive, poor conductors of heat and electricity
What are the general properties for lanthanides?
Highly reactive with halogens, burns easily in air, soft, silverish color, “rare earth metals”
What are the general properties for actinides?
Radioactive, highly reactive with most nonmetals, soft, silverish metals, “inner transition metals”
What is the trend for atomic radius?
Increases down a group, decreases across a period
Why does the trend for atomic radius occur?
Increases down due to more energy levels getting full, electron shielding remains the same across a period
What is a trend?
A predictable change in a particular direction
What is ionization energy?
The energy required to remove an electron from an atom or an ion
What is the trend for ionization energy?
Decreases down a group, increases across a period
What is the trend for electron shielding?
Increases down a group, remains the same across a period
What is the trend for atomic radius?
Increases down a group, decreases across a period
What is electronegativity?
A measure of the ability of an atom in a chemical compound to attract electrons
What is electron affinity?
The energy change when a neutral atom gains an electron
What is the trend for electron affinity?
Decreases down a group, increases across a period
What is the trend for ionic radius?
Increases down a group, cations & anions decrease
What are more physical properties of metals?
Luster, good conductors of heat & electricity, high density, high melting point, ductile, malleable
What are chemical properties of metals?
Easily lose electrons, called electron donors, corrodes easily, react with acids
What are the physical and chemical properties of nonmetals?
Gain electrons, electron acceptors, solids are dull and brittle, poor conductors, low melting and boiling points
What is an alloy according to the note slides?
A homogeneous mixture of two or more metals
When do high melting and boiling points occur?
When an orbital is half full
