Chemistry Unit 4 Review Sheet – Flashcards
Unlock all answers in this set
Unlock answersquestion
Atom
answer
The smallest unit of an element that maintains the chemical properties of that element
question
Element
answer
A substance that cannot be broken down into simpler substances by chemical means; all atoms of an element have the same atomic number
question
Compound
answer
A substance made up of atoms of two or more different elements joined by chemical bonds; contains definite composition that can be broken down into simpler substances by chemical methods
question
Physical property
answer
A characteristic of substance that doesn't involve a chemical change, such as density, color, or hardness
question
Physical change
answer
A change of matter from one form to another without a change in chemical properties
question
Change of state
answer
The change of a substance from one physical state to another
question
Solid
answer
The state of matter in which the volume and shape of a substance are fixed; there is a strong attraction between the particles
question
Liquid
answer
•The state of matter that has a definite volume but not a definite shape •particles constantly make and break temporary attractions b/t each other
question
Gas
answer
•A form of matter that doesn't have a definite volume or shape •particles are independent, very far apart, with no attractive forces between them •fill total volume of a container
question
Chemical property
answer
A property of matter that describes a substance's ability to participate in chemical reactions
question
Chemical change/reaction
answer
The process by which one or more substances change to produce one or more different substances
question
Reactants
answer
A substance or molecule that participates in a chemical reaction
question
Products
answer
A substance that forms in a chemical reaction
question
Mixture
answer
A combination of two or more substances that are not chemically combined
question
Homogeneous
answer
Describes something with one phase that has uniform properties and a uniform structure or composition throughout
question
Solutions
answer
A homogeneous mixture of two or more substances uniformly dispersed throughout a single phase
question
Heterogeneous
answer
Mixtures with more than one phase and variable properties in different parts of the sample. Composed of dissimilar components
question
Pure substance
answer
•composition is fixed or definite and always made up of the same elements in the same mass ratio •A sample of matter, either a single element or a single compound, that has definite chemical and physical properties
question
Molecule
answer
The smallest unit of a substance that keeps all of the physical and chemical properties of that substance; it can consist of one atom or two or more atoms bonded together
question
Alkali Metals
answer
A very reactive group- react violently w/ water They're all soft •low densities •low melting/boiling points
question
Alkali earth metals
answer
•Highly reactive but not as reactive as group one, but are harder and have higher densities and melting points than group 1 •present in the earths crust but not in their basic form
question
Halogens (nonmetal)
answer
•distinct color •low melting/ boiling point •very high electronegativities •highly reactive •can be harmful or lethal
question
Noble gases
answer
•Unreactive- will not form compound- single atoms •colorless •very low chemical reactivity •little tendency to gain/lose electrons
question
Metals (transition metals)
answer
•they form colored compounds •they are good conductors of heat/electricity •they can be hammered/bent to shape easily •they have high melting points/ density •Ductile & malleable •Shiny •Mostly solids
question
Nonmetals
answer
•generally poor conductors of heat/electricity- insulators •solid non-metals are generally brittle with little to no metallic luster •gain electrons easily •non-malleable •usually liquid/gas •Low density/ melting/ boiling points •high ionization energies and electronegativities
question
Metalloids
answer
Divide metals and nonmetals so they have properties of both
question
The First International Congress of Chemists did what?
answer
Settled the issue of atomic mass
question
Stanislao Cannizzaro
answer
Presented a convincing method for accurately measuring the mass of atoms allowing the chemists to agree on standard values for atomic mass
question
Dmitri Mendeleev
answer
Created the periodic table
question
Henry Mosely
answer
His work led to the modern definition of atomic number and recognized that the atomic number is the basis for the organization of the periodic table
question
Periodic Law
answer
•the physical and chemical properties of the elements are periodic functions of their atomic number; {so when the elements are arranged in order of increasing atomic number, elements with similar properties appear at different intervals}
question
Periodic Table
answer
An arrangement of the elements in order of their atomic numbers so that elements with similar properties fall into the same column/group
question
John William Strutt {aka Lord Rayleigh} and Sir William Ramsay
answer
Discovered the gases Argon and Helium so Ramsay proposed a new group: noble gases
question
In Dalton's Playhouse, during Priestly's experiment with the calx, what happened to the mass of the materials in the flask as it was heated?
answer
It decreased
question
What did you note about the masses of the gas produced and the Mercury metal left in the flask?
answer
The mass of the gas was the same as the mass of the metal.
question
What was the relationship between the volume of the gas produced and the mass of the calx that was heated?
answer
They were directly proportional; {as the volume went up so did the mass}
question
In Lavoiser's experiment with the phlogiston, with relation to the volume of the gases, in what specific proportion did phlogiston react with oxygen?
answer
2 H: 1 O
question
How did the mass of the gas in all three vessels before burning compare to the total mass after burning?
answer
They equalled each other because it was a closed system
question
In the diamond and charcoal experiment, how did the mass of the gas formed compare if you used the same amount of diamond and charcoal?
answer
The masses of the gas were equal
question
What is the core concept you can take away from experiment 1 with Priestly? And what law does it represent?
answer
Some substances are composed of discrete amounts of 2 or more other substances The Law of Definite Proportions
question
What is the core concept you can take away from experiment 2 with Lavoisier? And what law does it represent?
answer
The total mass of the products in a chemical reaction is exactly equal to the mass of the reactants. The Law of Conservation of Mass
question
What is the core concept you can take away from experiment 3 with the diamond? And what is the law it represents?
answer
Elements combine in specific, defined ratios in chemical reactions; Law of multiple (or definite) Proportions bc you had diamond and carbon
question
Empedocles
answer
Proposed 1 of the first theories attempting to explain the things around us
question
Democritus
answer
Came up with the idea of atomos (this mean indivisible) and developed new theory based on reasoning instead of science.
question
Aristotle
answer
Believed Empedocles' theory adding his own incorrect idea that 4 elements could be transformed into each other
question
Torricelli
answer
Invented the barometer saying air had mass, could exert force and could be measured
question
Priestly
answer
Englishman who experimented with red calx and observed it broke down into 2 substances when heated: a gas and liquid Mercury. Theory: substances can break down and come together to form a different substance
question
Lavoisier
answer
•Experimented dephlogisticated gas and proposed the theory that is made some some substances acidic renaming it oxygen •established the law of conservation of mass •discovered hydrogen burned with oxygen forms WATER
question
Dalton
answer
Developed the 1st modern atomic theory
question
Boyle
answer
•PRESSURE v.s. VOLUME law Discovered element was defined wrong and redefined it as a fundamental substance that cannot be broken down any further
question
Proust
answer
•gave us the law of definite proportions •said compounds have defined chemical formulas
question
Law of Definite Proportions
answer
•2 parts hydrogen + 1 part oxygen= water. •changing the proportions changes the substance
question
What are the 4 main concepts of Dalton's Atomic Theory?
answer
•all matter is composed of indivisible particles called atoms •all atoms of a given element are identical; atoms of different elements have different proportions •chemical reactions consist of the combination of atoms not the destruction •when elements react to form compounds, they react in defined whole number ratios
