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How many atoms are in a diatomic molecule?
2
What is accuracy?
Closeness to the true value
What is an isotope?
each of 2 or more forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nuclei, and hence differ in relative atomic mass but not in chemical properties.
What is a natural abundance?
the measure of the average a given isotope naturally occurring on earth
How do you calculate molar mass?
Go to periodic table and determine the atomic mass average (atomic weight) of each element. Multiply each atomic mass by the number of atoms in the formula. Add up the results of step three
What are 3 evidences that led to modern atomic theory?
1. Scanning Tunneling Microscope creates a "lumpy" image of matter
2. Brownian Motion
3. Avogadro's number: 6.022 x 10^23
What is the motion of a solid, liquid, and gas?
solid- vibrates but doesn't move
liquid-vibrates, moves about, slides past one another
gas- vibrate and move freely at high speed
What is in the spaces between gas particles?
empty space- as in nothing
Formula for Density
D= M/V
What is a statement summarizing a group of scientific facts called?
theory
What is the freezing point in celsius?
0
What is the freezing point in fahrenheit?
32
What is the boiling point of water in celsius?
100
What is the boiling point of water in fahrenheit?
212
What is an allotrope? Is carbon an allotrope- how?
An element that has another form - such as carbon, it can be graphite or a diamond
What is represented in a chemical equation?
Reactants --> Products
What makes a substance homogenous?
everything is uniform- it's near impossible to distinguish what makes up the substance
What makes a substance a pure substance?
substances that are made of only one type of atom or molecule.
What is the basis of the Kinetic Molecular Theory?
All matter consists of extremely tiny particles (atoms or molecules)
How do you convert pounds to kilograms?
1 pound equals 453.6 kg so multiply X by 453.6 to figure out how many kilograms are in a set of pounds
The small number to the top left of an element represents:
the mass #
The small number to the bottom left of an element represents
the atomic #
Atomic number is
the number of protons in an element
Mass number is
protons + neutron
The small number to the top right of an element represents the
net charge
What is Precision?
how close a series of measurements are to one another
What is Temperature?
An indicator of how much thermal energy is in a room
What is a substance?
A type of matter that has the same properties and the same composition throughout a sample.
Is a matter that doesn't separate homogenous or heterogenous?
homogenous
Law of the Conservation of Mass (in relation to reactants and their products)
The sum of the masses of the reactants equal the sum of the masses of the products
Whats true for an intensive property that isn't true for an extensive?
it is identical in all samples of a substance (color, density melting point)
What is the Law of Definite Proportions?
All samples of the same pure substance always contain the same elements in the same proportions by weight
Is matter continuous or particulate?
particulate
How do you calculate mass?
V x D
What is the Law of Constant Composition?
A chemical compound always contains the same elements in the same proportions by mass
What are the 4 assumptions of modern atomic theory?
1. All matter is composed of atoms, which are extremely tiny
2. All atoms of a given element have the same chemical properties
3. Compounds are formed by the chemical combination of two ore more different kinds of atoms
4. A chemical reaction involves joining, separating, or rearranging atoms
What form are metals at room temp?
solids, except for mercury (Hg) which is liquid
Most elements that are nonmetals consist of molecules on the _____scale
nano
What is an allotrope?
different forms of the same element in the same physical state at the same temp. and pressure
When atoms lose electrons, what happens to the charge?
it becomes positive
Do atoms have a charge?
no- they are electrically neutral
What is the name of subatomic particles that lack charge?
neutrons
What are the digits we write down from a measurement?
significant figures
What is the atomic number?
The number of protons within an atom
What is a mass number?
The total number of protons and neutrons
what is the formula for one mole?
6.022 x 10^23
Which columns are transition metals?
3-12
Which two columns are all main group metals?
1 and 2
What are the metalloids?
B, Si, Ge, As, Sb, and Te
What is the group below the metalloids composed of?
main group metals
What part of the periodic table is the least reactive?
noble gases
Are heterogenous mixtures uniform throughout?
No
What is a chemical compound?
A pure substance that can be decomposed into different pure substances (consists of 2 or more atoms combined.
What is the smallest particle in a compound?
a molecule
What is an element?
A substance that can not be decomposed into new substances.
What is the smallest part of an element?
An atom
What must be true of the components of a mixture that they can be separated?
They must have different physical properties
How many liters is one gas at standard room temperature?
22.4 liters
What is an extensive property? Give examples.
something that depends on specific sample under investigation. (mass, volume)
What is an intensive property? Give examples.
identical in all samples of a substance (density, color, melting point.)
What is the range for the melting / boiling points of a pure substance? Is it sharp?
about 2 degrees celsius. Yes.
What is the range for the melting / boiling point of a mixture? Is it sharp?
It is broad and dependent on the mixture
What is Density representative of?
mass per volume (g/mL)
What 3 things are representative of a Chemical Reaction?
1. Evolution of a gas
2. Change in color
3. Formation of a precipitate
What are the 3 parts of modern atomic theory?
1.Elements are composed of atoms which are very tiny
2. All atoms of a given element have the same chemical properties
3. Atoms are the fundamental units of Change
What 2 things must be true if matter is continuous?
1. We should be not be able to "sort" to a building block
2. The amount of different things in matter should not make a difference
What 4 things must be true is matter is particulate?
1. We should be able to find it
2. Specific ratios of the matter is important
3. Magnifying should show particles
4. They should be able to be measured and counted by methods
What is the rule regarding the # of significant figures in addition and subtraction?
the # of sig figs used in the answer is determined by the piece of data with the fewest number decimal places.
What is Rankin?
absolute scale using Fahrenheit size degree
What is an absolute scale?
a scale where there is 0 energy in the room
What is Kelvin?
An absolute scale using Celsius size degree
Boiling point of water according to Kelvin?
373 K
Room temperature according to Kelvin?
293 K
Freezing Point Temperature according to Kelvin?
273 K
What is absolute 0 in celsius?
-273 in C
At which point is fahrenheit equal to celsius?
-40 degrees
What are the 2 parts of Dalton's 1st postulate regarding Atomic Theory?
1. An element is composed of tiny particles called atoms
2. All atoms of a given element show the same chemical properties
What is Dalton's 2nd postulate regarding Atomic Theory?
Atoms of different elements have different properties
What are the 2 parts of Dalton's 3rd postulate regarding Atomic Theory?
1. Compounds are formed when atoms of 2 or more elements combine
2. In a given compound, the relative number of atoms of each kind are definite and constant
What are the 2 parts of Dalton's 4th postulate regarding Atomic Theory?
1. In an ordinary chemical reaction, no atom of any element disappears or is changed into an atom of another element
2. Chemical reactions involve changing the way in which the atoms are joined together
Are there physical or chemical differences between metals and non metals? Or both?
physical
If something can be mixed in something else it is _________________
miscible
What determines an atoms ID?
The number of protons
3 theories in relation to the makeup of an atom
1.) Mostly empty space
2.) Positively charged tiny nucleus
3.) Nearly all of atom's mass is in the nucleus