Chapters 1 & 2 Flashcards
Catch-Up before the actual learning
What is the central principle of modern chemistry?
Materials around us are composed of exceedingly small particles called atoms, and the precise arrangement of these atoms into molecules or more complicated structures accounts for the many different characteristics of materials
What does it mean to synthesize molecules?
Build large ones from small ones
What is an experiment?
An observation of natural phenomena carried out in a controlled manner so that the results can be duplicated and rational conclusions can be made.
What is a law?
A concise statement or mathematical equation about a fundamental relationship or regularity of nature. Example: Conversion of mass law - states the mass, or quantity or matter, remains constant during any chemical change
Hypothesis?
A tentative explanation of some regularity of nature.
What occurred during Rosenbergs experiment?
After seeing bacteria ceased to divide when an electric current from platinum wire electrodes passed through the culture, Rosenberg was eventually able to propose the hypothesis that certain platinum compounds were responsible.
What is a theory?
a tested explanation of basic natural phenomena. Example: Molecular theory of gases - the theory that all gases are composed of very small particles called molecules
Scientific method
The general process of advancing scientific knowledge through observation, the framing of laws, hypothesis or theories.
Balances measure mass
The quantity of matter in a material
What is the law of conversion mass?
The total mass remains constant during a chemical change (chemical reaction).
What is the weight of an object?
The force of gravity exerted on it
What are the two principal ways of classifying matter?
By it’s physical state (liquid, solid, gas) and by its chemical constitution (element, compound, mixture)
What are the differences between solids, liquids, gas?
Solids: have rigidity and maintain their shapes when subjected to outside forces.
Liquids and Gases: Are fluids that easily change their shapes. What distinguishes gas from liquid is that gas is easily compressible. While water is expansible.
What is vapour?
Gaseous state of any kind of matter that normally exists as a liquid or a solid.
What is a physical change?
A change in the form of matter but not in its chemical identity. Example:
Dissolving one material in another such as sodium chloride (table salt) in water. Distillation can be used to separate the components of the liquid.
What is a chemical change?
A change in which one or more kinds of matter are transformed into a new kind of matter or several new kinds of matter. Example: The creation of rust on iron
What is a physical property?
A characteristic that can be observed for a material without changing its chemical identity. Examples: (Physical state (solid, liquid gas), melting point colour.
What is a chemical property?
Characteristic of a material involving its chemical change. (production of rust)
Define substances
A kind of matter that cannot be separated into other kinds of matter by nay physical process. Example (water)
What is a element?
A substance that cannot be decomposed by any chemical reaction into a simpler substance.
What is a compound?
Substance composed of two or more elements chemically combined.
Joseph Louis Proust: The law of definite porportions?
A pure compound, whatever its source, always contains definite or constant proportions of the elements mass. Example (Sodium Chloride 1.0000g = .3934 grams of sodium and 0.6066 gram of chlorine.
What are mixtures?
A mixture is a material that can be separated by physical means into two or more substances. Unlike a purecompound, a mixture has a variable composition. Example: Sodium chloride dissolved into water is a mixture.
How are mixtures classified?
Heterogenous: Mixutre that consists of physically distinct parts, each with different properties (salt and sugr).
Homogenous mixture: Uniform in its properites throughout given samples. (soium chloride dissolved in water)
What is a phase?
One of several different homogenous material present in the portion of matter under a study. (A heterogenous mixture of salt and sugar has 2 phases - sale and sugar)
What was John Dalton’s atomic theory?
All matter - whether element, compound, or mixture - is composed of small particles called atoms.
Postulates of Dalton’s atomic theory?
- All matter is composed of invisible atoms.
- An element is a type of matter composed of only one kind of atom
- A compound is a type of matter composed of atoms of two or more elements chemically combined in fixed proportions.
- A chemical reaction consists of the rearrangement of the atoms present in the reacting substances to give new chemical combinations present in the substance formed by the reaction.
What is an atomic symbol?
One or two-letter notation used to represent an atom corresponding to a particular element.
What is the law of conservation of mass?
The total mass remains constant during a chemical reaction.
Law of Multiple proportions deduced by Dalton?
When two elements form more than one compound, the masses of the element in these compounds for a fixed mass of the other element are in ratios of small whole numbers.
Atoms consist of two kinds of particles
Necleus (the atoms central core, postively charged and contains most of the atoms mass)
Electron (a very light, negatively charged particle that exists in the region around the atoms positively charged nucleus)
Who was J.J. Thompson
He conducted a series of experiments that showed that toms were not indivisible particles.
What is the nucleus of an atom comprised of?
protons and neutrons
What is the atomic number
An elements unique nuclear charge. The number of protons in the nucleus of the atom.
What is a proton?
A nuclear particle having a postiive charge equal in magnitude to that of the electron and a mass more than 1800 times that of the electron
What is an element in relation to atoms?
An element is a substance whose atoms all have the same atomic number.
What is a neutron?
A nuclear particle having a mass almost identical to that of the proton but no electric charge.
How is a nucleus characterized?
- By atomic mass
- Mass number (total number of protons and neutrons in a nucleus.
What is a nuclide?
An atom characterized by an atomic number and mass number.
What are isotopes?
Atoms whose nuclei have the same atomic number but different mass numbers; that is, the nuclei have the same number of protons but different number of neutrons.
Atomic Masses
As Dalton found that elements have consistent weights but we know that various isotopes have their own characteristic masses, we know that Dalton was measuring the average atomic masses.
What is an atomic mass unit?
A mass unit equal to exactly one-twelfth the mass of a carbon-12 atom.
What is the fractional abundance of an isotope?
The fraction of the total number of atoms tat is compose of a particular isotope.
How do you calculate the atomic mass of an element?
Multiplying each isotopic mass by its fractional abudnance and summing the values.
Who created the periodic table of elements?
Dmitiri Mendeleev
What is a metal?
A substance that has a characteristic luster, or shine, and is generally a good conductor of heat and electricity.
What is a non-metal?
A metalloid or semimetal is an element having both metallic and nonmetalic properties. These are generally good semiconductors.
What is a molecule?
A definite group of atoms that are chemically bonded together - that is, tightly connected by atractive forces.
What is a molecular formular?
Gives the exact number of different atoms of an element in a molecule.
What is an ionic substance?
Electrically charged particle obtained from an atom or chemically bonded group of atoms by adding or removing electrons. Example Sodium Chloride
What is an anion?
An atom that picks up an extra electron becomes a negatively charged ion.
What is cation
An atom that loses an electron and becomes positively chargedI
What is an ionic compound?
Substances composed of ions. Most contain metal and nonmetal atoms such as NaCL
What is a monatomic ion (used for naming ionic compounds)
An ion formed from a single atom.
Elements that have one valence electron usually form an ion with how many charges?
Elements that typically have 1 valence electron will usually form ions with a +1 charge.
Metals typically form positive or negatively charged ions?
Postive
Non-Metals typically form positive or negatively charged ions?
Negative
What is a polyatomic ion?
It is an ion consisting of two or more atoms chemically bonded together and carrying a net electric charge
How do you name polyatomic ions?
The suffix “-ate” will always be for the highest oxygen provided polyatom - such as PO4 (Phosphate) or SO4 (Sulfate)
The prefix “per” is added if the polyatomic ion has one more oxygen then SO4 (with the suffix -ate” —> So S05 (perchlorate)
The suffix “-ite” will have one less oxygen then what is above. such as PO3 (Phosphite) or SO3 (Sulfite)
The prefix “hypo-“ is added if the polyatomic ion has one less oxygen then PO3 (or that of -ite) - –> So SO2 will be hypophosphite
The suffix “-ide” is for a monotomic ion that doesn’t have oxygen. Such as P- (Phosphide) or S- (Sulfide). In the event a monoatomic ion has multiple ions, the use of a roman numeral denotes it so if it’s Fe+2 (Iron (II))
What are binary compounds?
Composed of only two elements. A metal and a non-metal
How do you distinguish an ionic compound from a molecular compond?
Ionic compounds have ions (charges) + it is also composed of a metal and a non-metal with the exception being ammonium nitrate which is still ionic (NH4NO3)
What is an oxoacid?
An acid containing hydrogen, oxygen, and another element (often called the central atom)
Naming acids and corresponding anions
If it contains a polyatomic ion with the word:
-ate –> it changes to “-ic” + acid
-ite –> it changes to “-ous” + acid
-ide –> Add the prefix “hydro-“ + the suffix “-ic” + Acid
Example:
H2S04 - contains S04 which is an acid because it contains a (2-) –> This changes it from sulfate to sulfuric acid
H2S03 –> SO3 –> Sulfite –> Sulfurous acid
HClO4 -> perchlorate -> perchloric acid
