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Chemistry I Exam I
Terms in this set (114)
---is the fundamental unit of an element and it's composed of the 3 subatomic particles.
--- is the smallest quantity of matter that still retains the properties of matter.
--- is a substance that cannot be broken down into two or more simpler substances by any means. Ex. gold, oxygen, helium
--- --- --- states that matter is composed of small, indivisible particles called atoms.
Modern Atomic Theory
--- --- --- states that matter can neither be created nor destroyed, all that happens is that it changes forms.
The Law of Conservation of Mass
According to the --- --- ---, all samples of a compound no matter their origin or preparation has the same mass ratio in terms of their elements. (Mass doesn't matter; ratio will always be the same)
Law of Definite Proportions
No matter where you obtain a compound, whether it's from a lab experiment or from collection out in the field, the ratio of elements in it will remain ---.
When element A and element B combine they can form different compounds in different ratios to one another. Dividing these different ratios should generate --- --- answers.
According to the --- --- --- when two elements (A and B) form different compounds, the masses of element B that combine with 1g of A are a ratio of whole numbers.
Law of Multiple Proportions
The --- --- represents the identity of the element and reveals the number of protons, whereas the --- --- reveals the number of protons and neutrons.
atomic number; atomic mass
In the center of the atom there is the ---
The nucleus contains 2 subatomic particles:
protons and neutrons
Spinning around the nucleus is the 3rd subatomic particle, the ---
Protons are ---- charged subatomic particles.
Electrons are ---- charged subatomic particles.
Neutrons are ---- charged subatomic particles.
The nucleus has an overall --- charge.
The --- --- equals the number of protons and determines the identity of an elements.
--- --- equals the number of protons and neutrons in an element.
The number of --- gives the identity of an element.
--- arise when atoms lose or gain electrons and the atom acquires a charge. There is an unbalance between the atoms protons and electrons.
The atomic number equals the number of --- and determines the ---of an elements.
The atomic mass equals the number of --- and --- in an element.
protons and neutrons
--- --- created the Modern Atomic Theory in 1803-1807
The positive proton and the negative electron will add together to state the --- of the element.
In the late 1800s, many scientists were doing research involving ---, the emission and transmission of energy in the form of waves.
They commonly used a --- --- ---, which consists of two metal plates sealed inside a glass tube from which most of the air has been evacuated.
cathode ray tube
J.J. Thompson's 1897 cathode ray tube experiment led to the discovery of the ----
Thomson discovered that all metal surfaces produce --- --- which have --- charged particles called ---.
cathode rays; negatively; electrons
Thomson discovered that electric and magnetic fields --- the beams of energy due to different charges.
Thompson discovered the --- to --- ratio of the electron by varying the electric field and measuring the degree of deflection of cathode rays.
C is coulomb, the SI unit of electric charge
--- 1911 studied electrically-charged oil drops.
R. A. Millikan determined the --- --- by examining the motion of tiny oil drops.
charge of an electron
Thompson proposed the --- --- model of an atom, where positive and negative charges were squished together like a chocolate chip cookie.
plum pudding model
The --- led to the discovery of the highly dense center within a given atom.
Rutherford Gold Foil Experiment
Rutherford proposed a new model for the atom: --- ---
The --- accounts for most of an atom's mass and is an extremely dense central core within the atom.
Atoms are mesured in ---
atomic mass units or amu
Most elements have two or more ---, atoms that have the same atomic number but different atomic mass.
Isotopes are atoms that have the same --- --- but different --- ---.
atomic number; atomic mass
Isotopes of the same element typically exhibit very similar --- properties.
Isotopes of an atom have a different number of ---.
The --- --- --- on the periodic table represents the average mass of naturally occurring mixture of isotopes.
average atomic mass
Each isotope contributes to the average atomic mass based on its --- ---. Multiplying the --- of each isotope by its fractional abundance (percent value divided by 100) will give its contribution to the average atomic mass.
relative abundance; mass
a --- is a combination of at least two atoms in a specific arrangement held together by chemical forces (chemical bonds)
A molecule may be an --- or a ---.
are molecules composed of only two atoms, of the same or different chemical elements.
Diatomic molecules containing only two atoms of the same element are called
homonuclear diatomic molecules
Diatomic molecules containing only two atoms of different elements are called
heteronuclear diatomic molecules
--- --- contain more than two atoms of different elements.
a ---- --- shows the exact number of atoms of each element in a molecule. It represents the actual or true whole number ratio.
A(n) ---- ---- is also known as the simplest formula. It represents the smallest whole number ratio of moles of each element in a compound.
--- are two or more different physical forms in which an element can exist. Ex: Carbon can be graphite, diamonds, or charcoal.
A --- --- shows not only the elemental composition, but also the general physical arrangements; shows the number of atoms and the bonds between them.
(True/False) If any coefficient(subscript) in the molecular formula is 1, then the molecular formula and empirical formula are the same.
The --- --- is a chart in which elements having similar chemical and physical properties are grouped together.
Elements are arranged in ---, horizontal rows, in order of increasing atomic number.
On the periodic table elements can be catogorized as ---, ---, or ---.
metals, nonmetals, metalloids
--- are the elements that make up the staircase. They are shiny, semiconductors, and used frequently in technology. They are hybrids of metals and nonmetals.
--- are the elements to the right of the staircase and hydrogen. They are brittle and dull. They are poor conductors and insulators. They occur in all physical states.
--- are all the elements to the left of the staircase. They are solid, shiny, good conductors, ductile, malleable, and reflective.
A vertical column on the periodic table is known as a ---.
Group 1A elements (Li, Na, K, Rb, Cs, Fr) are called --- ---. They have one valence electron in the outermost shell; therefore they are highly reactive.
Group 2A elements (Be, Mg, Ca, Sr, Ba, Ra) are called --- --- ---. They have 2 valence electrons in their outermost shells.
alkaline earth metals
Group 6A elements (O, S, Se, Te, Po) are called ----. They have 6 valence electrons in their outermost shell.
Group 7A elements (F, Cl, Br, I, At) are called ---. They are extremely reactive because they have 7 valence electrons in their outermost shell.
Group 8A elements (He, Ne, Ar, Kr, Xe, Rn) are called the --- ---. They have 8 valence electrons, and they are nonreactive.
Groups 1B and 3B-8B are called the --- --- or --- --- because they have different oxidation phases. They can choose how they want to lose or gain electrons.
transition elements/transition metals
Of the more than 110 elements currently known, how many are natuarlly occuring and how many are synthetic?
90 occur naturally on earth
the rest are man made (about 20)
Ionic compounds are electrically --- because the charges --- ---
neutral; cancel out
In order for ionic compounds to be electronically neutral, the sum of the charges of the cation and anion in each formula must be ---.
What is a positively charged ion?
What is a negatively charged ion?
When neutralizing ionic compounds, one can simply take the charge of the cation/anion and make it the --- of the other cation/anion.
--- --- is the weighted average mass of an atom of an element based on the relative natural abundance of that element's isotopes. --- --- is a count of the total number of protons and neutrons in an atom's nucleus.
atomic mass; mass number
Some of the atoms in the Periodic Table are very predictable. They are called the --- --- elements. They are groups IA-VIIIA.
The atoms that are NOT predictable are in the middle chunk of the Periodic Table. These are called the --- elements. They are groups IIIB -IIB.
Ions that have more than one atom are called --- ---. When they are "squishing" ions together, they always travel in packs.
--- --- are formed only by groups of nonmetal elements.
--- --- are formed by groups of non-metals and metals.
For main group metal-nonmetal binary compounds can only form one kind of cation so the name is easy. SO how do you name a Metal-Nonmetal compound?
name the metal first, then the nonmetal with an -ide ending.
Transition metal compounds can spuish together with nonmetals in multiple ways since they can have different charges. What are the two approaches to naming these compounds?
1. the "common" name approach
2. the "Roman numeral" approach
How do you name a transitional metal compound using the Roman numeral approach?
1. put in a Roman numeral in parentheses after the metal that indicates its CHARGE NUMBER
2. name the nonmetal with an -ide ending.
How do I figure out what charge the metal is when naming a transitional metal compound?
I know what the charge is on the nonmetal part, so I can figure out what the metal charge. I have to neutralize the compound.
How are compounds with polyatomic ions named?
Naming compounds with polyatomic ions is treated the same way as regular metal-nonmetal compounds. You name the metal first and then treat the polyatomic ion as a nonmetal and then name the polyatomic ion. Also determine if the metal is a main group metal or transition metal to see if you need to add Roman Numerals.
--- compounds are when you take two NONMETALS and squish them together.
--- means they are sharing electrons instead of becoming ions.
How do you name Covalent compounds?
Name the element that occurs the most left in the periodic table first and then use Greek prefixes to indicate the number of each element. If two elements are in the same group of the periodic table, put the one first that is further down the group.
Some compounds have water loosely bond around the outside of the molecule. These are called ---
How do I name hydrates?
Name the ionic compound first and then name the water according to covalent compound rules as it is a covalent compound.
--- are anions that contain lots of oxygens. (Most of these are polyatomic ions that are memorized.)
--- compounds have one or more hydrogens attached to the anion.
There are two types of acid compounds. What are they and how do you name them?
1. Binary acids: put in -hydro and then name the root -ic acid
2. Oxo-acids: start with the oxoanion name. If oxoanion has an -ate ending, it becomes an -ic acid; if the oxoanion has an -ite ending, it becomes an -ous acid
What is Avogadro's number? And what does it represent?
it is the number of how many atoms are in one mole; allows working with atoms to be more manageable; gives us a conversion factor
--- --- is used for those substances whose constituent particles are ions. This is the sum of the atomic masses of all the atoms in the formula unit of a compound and is calculated in the same way as molecular mass.
What is molar mass?
mass of 1 mole of any substance
atomic mass of an element = molar mass of the element
What is a mole?
A mole is equal to the molecular mass of one atom, the formula mass of one atom, and Avogadro's number
-its a conversion factor
--- --- is the sum of the atomic masses of all the atoms present in a molecule of that substance.
A list of the percent by mass of each element in a compound is known as the compound's --- --- ---.
percent composition by mass.
What is the equation to find the percent composition of compounds?
percent mass of an element = ((n)atomic mass of element/ molecular or formula mass of compound) 100
*where n is the number of atoms of the element in a molecule or formula unit of the compound
What is percent composition?
looking for how much of this element is in a particular compound in percent form
a --- is a substance dissolved in another substance
What is the component of a solution that is present in the greatest amount, the one in which the other is dissolved?
How do I determine percentage of an element if given a molecular compound?
-for each element multiply the number of atoms by the atomic mass, divide by the formula mass, and multiply by 100%
How do I determine empirical formula starting with % or masses?
1. assume 100g sample > % becomes mass in grams
2.Divide each mass by the elements atomic mass > gives the number of moles of each
3. divide each by the smallest number of moles found > the smallest whole number ratio is the empirical formula
How do I convert the empirical formula into the molecular formula using molar mass?
1. find the empirical formula
2. if we know the approximate molar mass of the compound, we can determine the molecular formula
3. Divide the molar mass by the empirical formula mass
4. multiply the empirical formula by the number you received from the molar mass and empirical mass to obtain the molecular formula
--- is defined as the number of moles of solute per liter of solution.
Molarity = moles/liters
In Molarity problems you are often asked to determine the molar concentration of separate ions in solution. How do you find that?
1. find the molarity of the compound as a whole
2. multiply the number of the ion/element that occurs in the compound by the total molarity of the compound = the molar concentration of the singular ion/element
What equation is used for dilutions?
moles of solute before dilution = moles of solute after dilution
M1 x V1 = M2 x V2
--- is the process of preparing a less concentrated solution from a more concentrated one.
A series of dilutions that may be used to prepare a number of increasingly dilute solutions is called --- ---.
Because the atomic masses on the periodic table are average atomic masses, the result of such a determination is an average molecular mass, sometimes referred to as the --- ---
What is the path to follow when converting grams, moles and particles?
grams > moles > particles
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