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Chemistry TCB Exam Flashcards
Cards to help you study for the testing out exam on June 3
97
Chemistry
8th Grade
05/17/2011

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Cards

Term
chemistry =
Definition
study of substances and the changes they undergo
Term
Describe the Atlantic/Pacific rule.
Definition

decimal Absent: start on the Atlantic side of the number, count the first non-zero number and all that follow

decimal Present: start on Pacific side of the number, count the first non-zero number and count all that follow

Term
How many sig figs do I use when measuring things in lab situations?  (ex. graduated cylinder or ruler)
Definition
go to the nearest line given, then estimate one decimal past that (if a graduated cylinder shows lines every 1mL, your answer should be to the nearest 1/10mL  ex. 10.5mL)
Term
accuracy
Definition
how close a measurement is to the real answer
Term
precision
Definition
how close a measurement is to other measurements
Term

How many sig figs in:

7.2340

0.03460

1,340.01

Definition

5

4

6

Term
How do we measure density?
Definition
mass/volume
Term

Put the following in scientific notation:

5,245,252

0.00346

Definition

5.25x10^6

3.46x10^-3

Term
If I shoot my bow, and I consistently hit low and to the left, are my shots precise or accurate or both?
Definition
precise (the shots are consistent, but not accurate, that is, they're not close to the bullseye)
Term

Convert the following:

1,288 inches = ____? meters

2.54cm / inch

Definition

3,271.52cm

or

3,270cm (3 sig figs)

Term
independent variable
Definition
the thing I change/control
Term
dependent variable(s)
Definition
the thing(s) you measure
Term
law of conservation of energy
Definition
energy is neither created or destroyed
Term
law of conservation of mass
Definition
mass is neither created or destroyed
Term
law of conservation of matter
Definition
matter is neither created or destroyed
Term

Which can NOT be broken down any further?

sodium, disulfate, diatomic oxygen, hydroxide

Definition
sodium, because its an element.  The rest are either molecules or compounds
Term
Is a phase change a chemical change or a physical change?
Definition
Physical change because its only changing forms, not creating something new
Term
chemical change
Definition
when a chemical reaction takes place and new products are formed
Term
Which state of matter is typically the LEAST dense?
Definition
Gas
Term
What is an alpha particle?
Definition
a helium nucleus (2 protons, 2 neutrons)
Term
How do you balance nuclear equations?
Definition
balance the top number (mass number) and balance the bottom number (atomic number)
Term
If the result of a nuclear equation is a particle with a mass number of 4 and atomic number of 2, what type of nuclear reaction happened?
Definition
alpha decay, because an alpha particle has an atomic # of 2 and mass # of 4.
Term
If the result of a nuclear equation is a particle with a mass number of 0 and atomic number of -1, what type of nuclear reaction happened?
Definition
beta decay, because the result of beta decay is the decay of a neutron into a proton and the release of an electron
Term

Match the scientist:

Bohr                   gold foil experiment

JJ Thomson        planet model of atom

Rutherford                      plum pudding

Definition

Bohr:  planetary model

Thomson:  plum pudding

Rutherford:  gold foil

Term
What did the gold foil experiment done by Rutherford prove?
Definition
atoms have very tiny, but very dense nuclei
Term
If I started with 48g of Carbon-12, and 1yr later I have 38g, what term describes what has happened?
Definition
radioactive decay
Term
If the half-life of carbon-12 is 5.73yrs, and I started with 100g, how much is left after 11.46yrs?
Definition

25 grams

because 11.46yrs is 2 half-lives

100g-->50g-->25g

Term
How many half-lives does it take to have 1/16 of the original sample left?
Definition

4 half-lives

1-->1/2-->1/4-->1/8-->1/16

Term
If the mass number of element X is 48, and it has 22 protons, how many neutrons does it have?
Definition

26 neutrons

48 - 22 = 26

Term
If the atomic number of element X is 43 and it contains 41 electrons, what is the ion charge?
Definition

+2

 

Term

What does the neutron do for an atom?

 

Definition

Three important things:

1.  it supplies the force that holds the nucleus together

2.  it makes the atom more stable

3.  it is the "glue" of the nucleus

Term

What is the atomic mass of element X:

isotope 1: 18.32amu, abundance 21.30%

isotope 2: 19.27amu, abundance 70.20%

isotope 3: 20.11amu, abundance 8.50%

Definition

19.14amu

18.32 x .2130 = 3.90

19.27 x .7020 = 13.53

20.11 x .0850 = 1.71

Term
electrons have several energy levels, which contain _____, which contain _______ that each hold a pair of electrons.
Definition

sublevels

orbitals

Term
s, p, d and f describe what?
Definition
electron sublevels (and areas on the periodic table that contain those sublevels)
Term
What is the shape of the s-sublevel?
Definition
sphere
Term
What is the shape of the p-sublevel?
Definition
dumb bell shape
Term

How many valence electrons do the following have?

Na, C, Ne

Definition

Na = 1

C = 6

Ne = 8

Term
What element has the same electron configuration as Al+3?
Definition

Neon

because aluminum lost 3 electrons, giving it the same configuration as the element with 3 less electrons

Term
If we vaporize an element in a flame, what type of light is given off?
Definition
only specific wavelengths of light, which are based on the energy given off by the electrons as they fall back to their "ground state"
Term
What color of light has the highest energy? lowest?
Definition

highest: violet

lowest: red

Term
What is the electron configuration for Fe (iron)?
Definition
1s2, 2s2, 2p6, 3s2, 3p6, 4s2, 3d8
Term
Why are valence electrons important?
Definition
they are the electrons involved in reactions and bonding
Term
What halogen has the highest ionization energy? Why?
Definition
Fluorine because its outermost electron is closest to the nucleus
Term
ionization energy
Definition
energy needed to "pluck" an electron from an atom;  increases as you go right and up on the periodic table
Term
Ionization energy is similar to what other trend on the periodic table?
Definition
electron affinity
Term
atomic radius
Definition
measure of the size of an atom; it increases down a group, but decreases across a period
Term
Why does atomic radius decrease across a period?
Definition
because as electrons and protons are added, the attraction between the nucleus and electrons increases, making the atom more "condensed"
Term
When an atom gains electrons, it
Definition

gets larger

becomes an ion

has a negative charge

Term
Metals typically form ___ ions and are found on the ___ of the periodic table.  Non-metals typically form ___ ions and are found on the ___ of the periodic table.
Definition

positive, left

negative, right

Term
What is the difference between ionization energy and electron affinity?
Definition

ionization energy= energy required to "pluck" an electron from the atom

electron affinity= energy given off when an electron is gained

Term
Which "block" contains the alkali metals and alkaline earth metals?
Definition
s-block
Term
Which "block" contains the non-metals?
Definition
p-block
Term
Which "block" contains the transition metals?
Definition
d-block
Term
What makes transition metals unique?
Definition

They are:

good conductors of heat/electricity

shiny, malleable, ductile

Term
What makes alkali metals and alkaline earth metals unique?
Definition
they are highly reactive, soft metals
Term
What makes the halogens unique?
Definition
they are highly reactive non-metals
Term
Air is a mixture of gases including oxygen, nitrogen, helium, hydrogen and traces of other gases.  Which gas makes up most (70+%) of earth's air?
Definition
nitrogen
Term
Which "block" on the periodic table is the only one that contains both metals and non-metals?
Definition
p-block
Term

What is the formula for the following:

sulfate

sulfide

ammonia

ammonium

Definition

SO4-2

S-2

NH3

NH4+1

Term
When atoms lose or gain electrons, they are trying to form stable electron configurations similar to which family?
Definition
noble gases
Term

Name the compound:

NaNO3

SBr3

CaF2

KCl * 5H2O

Definition

sodium nitrate

sulfur tribromide

calcium fluoride

potassium chloride pentahydrate

Term
When is the prefix "mono" used in naming compounds?
Definition
only on the second word of a covalent compound, never on the first.
Term

What does the Roman numeral next to a transition metal tell you?

ex. copper (II) sulfate

Definition
it tells you the ion charge (positive) on the transition metal
Term

What does an acid have in its formula?

What does a base have in its formula?

Definition

H+ ion

OH- ion

Term
Which is the stronger covalent bond, a single bond or double bond or triple bond?
Definition
triple is strongest, then double, then single
Term
Which covalent bonds are the longest, single, double or triple bonds?
Definition
single bonds are longest, then double, then triple
Term
How many single covalent bonds can one carbon atom have?
Definition
4
Term
alkane
Definition

single chain hydrocarbon with the formula

CnH*2n +2

ex. C8H18

Term
What does "Max eats peanut butter" refer to?
Definition

naming alkanes and alcohols

Max = methane/methanol

eats = ethane/ethanol

peanut = propane/propanol

butter = butane/butanol

Term
allotrope
Definition
a pure substance with different structural forms
Term
What are the three most common allotropes of carbon?
Definition

graphite

diamond

buckminster fullerine (buckyball)

Term
alcohol
Definition

a hydrocarbon in which a hydroxide (OH) has replaced CH3 on one side of an alkane

ex. ethane = CH3CH2CH3

ethanol = CH3CH2OH

Term
What are alcohols most used for?
Definition
they are burned for fuel
Term
alloy
Definition
a mixture containing metals produced by melting them together
Term

Which of the following is NOT an alloy?

steel

bronze

silver

brass

Definition
silver, it is an element
Term
molarity
Definition

moles per liter

mol/L

Term
molality
Definition

moles per kilogram

mol/kg

Term
What formula do we use to calculate Molarity?
Definition
Molarity = # mols / molar mass
Term
In words, what is molarity?
Definition
concentration of a substance in a liquid (usually water)
Term
How do we figure out the number of mols of a substance?
Definition
# mols = grams of substance / molar mass
Term
How do we figure out molar mass?
Definition

1. Look up each element's mass

2. Multiply by the # of atoms of that element

3.  Add all the numbers together

Term
What is Avogadro's Number?
Definition

6.02 X 10^23

or 1 mole

Term
How do we calculate the number of particles of a substance?
Definition
# particles = (# mols ) X (6.02 X 10^23)
Term

What type of reaction is shown below?

 

2HgO --->  2Hg + O2

Definition
decomposition reaction
Term

What type of reaction is shown below?

 

2Mg + O2 --->  2MgO

Definition

combination reaction OR

synthesis reaction

Term

What type of reaction is shown below:

 

2K + 2H2O --->  2KOH + H2

Definition
single replacement reaction
Term

What type of reaction is shown below:

 

Br2 + 2NaI --->  2NaBr + I2

Definition
single replacement reaction
Term
What must be true for a metal to replace another metal (or hydrogen) in a single replacement reaction?
Definition
it must be more reactive (from the activity series chart) than the one it replaces
Term

What type of reaction is shown below:

 

Na2S + Cd(NO3)2 --->  CdS + 2NaNO3

Definition
double replacement reaction
Term

Balance this reaction:

 

NaCN + H2SO4 --->  HCN + Na2SO4

Definition
2NaCN + H2SO4 --->  2HCN + Na2SO4
Term

Balance this equation, give the type of reaction and name the compounds:

 

Ca(OH)2 + HCl --->  CaCl2 + H2O

Definition

Ca(OH)2 + 2HCl --->  CaCl2 + 2H2O

double replacement reaction

calcium hydroxide + hydrogen chloride (hydrochloric acid)  ---> calcium chloride + dihydrogen monoxide (water)

Term

What type of reaction is shown below,  and name the compounds:

 

2C8H18 + 25O2 --->  16CO2 + 18H2O

Definition

combustion (burning) reaction

 

octane (gasoline) + diatomic oxygen (oxygen gas) --->  carbon dioxide + dihydrogen monoxide (water)

Term
How many total electrons are involved in a double covalent bond?
Definition
4
Term
polarity
Definition
describes if a molecule has a positive side and a negative side; like a magnet
Term
How do we determine whether a molecule is polar or non-polar?
Definition

check the electronegativity chart: 

a difference greater than 0.4 means polar...if the molecule is diatomic, it must be non-polar

Term
electronegativity
Definition
a number given to elements to describe "how negative" or "how positive" they are
Term

Determine if the following is polar or non-polar:

Na2S

O2

TeCl2

Electronegativities: Na=0.9  S=2.5  O=3.5  Te=2.1  Cl=3.0

Definition

Na2S  --->  polar (EN:  2.5-0.9=1.6)

O2 ---->  non-polar (diatomic)

TeCl2 ----> polar (EN: 3.0-2.1=0.9)

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