chemistry fall final

in which side is energy known to be released?

product side

Which liquid has the highest vapor pressure at 75*?

propane

what is matter

pure mixture of substances

ozone is______ to use and ______________

safer; environmentally

what is the total number of moles of sulfur atoms in 1 mole of Fe2(SO4)3

(1mol Fe2(SO4)3 x 3 mol sulfur)/1mol Fe2(SO4)3 =3 moles

heated, one of the products is CO2 as shown in the equation: 2NaHCO3 + heat ---> Na2CO3 + H2O + CO2 find # of moles of CO2 produced when 7 moles of NaHCO3 is completely reacted

(7 moles NaHCO3 x 1 mol O2)/2 mol NaHCO3 =3.5 mole

whcih fromula is correct for ammonium sulfate

(NH4)2SO4

what is the total number of moles of atoms present in 1 gram formula mass of Pb(C2H3O2)2

(Pb:1 C:4 H:6 O:4) 15 moles

ionic amount

1.7+

at which celsius temperature does lead change from a solid to a liquid

328*

oxygen has a double bond bc the 2 atoms of oxygen share a total of

4 electrons

what is the atomic # of an element that has 6 p+ and 8n0?

6

which statement explains why sulfur is classified as a group 16 element

6 valence electrons

the total mass of the p+ in an atom of gold-198 is about

79 atomic mass

other gases in the PT include

N O F H Cl

which compound has Hydrogen bonding between its molecules

NH3

which of these elements has an atom with the most stable outer electron config.?

Ne

Rutherford Experiment

bombarded gold foil with alpha particles. showed atoms were mostly empty space with small, dense positively charged nucleus.

I+I->I2

bond is broken and energy is released

magnesium nitrate contains chemical bonds that are

both covalent and ionic

in which compound is the ratio of metal ions to non-metal ions 1 to 2?

calcium bromide (ca+2 and Br+1- criss cross)

which substance can be broken down by a chemical change

carbon

which polyatomic ion contains the greatest # of oxygen atoms

carbonate (CO3^2-)

the name of the compound KClO2 is potassium

chlorite

all chemical reactions show

conservation of MASS, ENERGY & CHARGE

what element has the greatest density at STP?

copper

What are physical properties?

density conductivity malleability hardness ductility solubility

oxygen and its family form what kind of bonds? nitrogen and its family form what kind of bonds? carbon however can form____ and ______ bonds with itself

double bonds; triple bonds; double and triple

Dalton's model

elements are made of atoms, atoms of an element are the same, compounds are formed from combinations of atoms

During a flame test, ions of a specific metal are heated in the flame of a gas burner. A characteristic color of light is emitted by these ions in the flame when the electrons...

emit energy as they return to lower energy levels

an experiment in which alpha particles were used to bombard thin sheets of gold foil led to the conclusion that an atom is composed mostly of

empty space and has a v small charged nuclues

breaking chemical bond forming chemical bond

endothermic; exothermic

heated, one of the products is CO2 as shown in the equation: 2NaHCO3 + heat ---> Na2CO3 + H2O + CO2 endo or exo?

endothermic; heat

Cl2->Cl+Cl

energy is absorbed and a bond is broken

how can you separate mixtures?

evaporation filtration (solids separated from liquid) chromatography (separates the difference in solubility of a substance) distillation (difference in boiling points)

non-polar molecules have

even distribution or electrons; dissolved only by another non-polar substance

elements are arranged by

periods (down aka energy levels) and groups (across) and increasing atomic number

When an atom loses an electron it becomes (metals)

positive ion & radius decreases (loses mass small)

Group 18 are

noble gases and have high ionization energies (unreactive)

at standard pressure, a certain compound has a low boiling point and is insoluble in water. At STP this compound most likely exists as

non polar molecules

elements to the right of the staircase are

non-metals dull not conductors brittle high ionization and electronegativities

Where are protons and neutrons found? What is tru about protons?

nucleus of an atom (nuclear charge=#of p+) protons=electrons p+ and n0 have the same mass p+ + n0=atomic mass mass contained in nucleus

valence e- are the _______; they affect_____properties of this element

outermost e-; chemical;

how to find mass number?

p+ + n0

a double carbon carbon bond is found in a molecule of

pentene

percent composition is

percent error

iso. atomic mass %abundance Si-28 27.89 92.22 Si-29 28.98 4.69 si-30 29.97 3.09 a scientist calculated the %natural abundance of Si-30 in a sample to be 3.29%. Find the %error.

%error= (3.29-3.09)/3.09 x100 =6.47%

A hydrated compound contains water molecules within its crystal structure. The percent composition by mass of water in the hydrated compound CaSO4•2H2O has an accepted value of 20.9%. A student did an experiment and determined that the percent composition by mass of water in CaSO4•2H2O was 21.4%. Calculate the percent error of the student's experimental result. Your response must include both a correct numerical setup and the calculated result.

%error= 21.4-20.9/21.4 x 100 =2.4%

which particle diagram represents one compound

1 atom from each element combined

what is a pure substance

(element or compound) that has a constant composition and constant properties throughout a given sample, and from sample to sample

the # of moles in a 12g sample of Cl2 is

(given mass)12g/(molar mass)71g (mass to mole)

given the reaction 4NH3 + 5O2-> 4 NO + 6H2O what is the total # of moles of NO produced when 1 mole of O2 is completely consumed?

(given mole of O2 x unkknown # of NO mol)/actual # of O2 mol =0.80 mole

what is the nuclear charge of an iron atom

+26

non-polar covalent amount

0.0

polar covalent amount

0.0-1.7

heated, one of the products is CO2 as shown in the equation: 2NaHCO3 + heat ---> Na2CO3 + H2O + CO2 1. Write a numerical setup for calculating the percent composition by mass of carbon in the product Na2CO3

12 (mass of c)/22.99(2)+12.01+16(3) [total mass of Na2CO3] x100 =11.3%

C-14 what does the C 14 and 6 mean?

14- # of isotopes 6-atomic number

an atom of flourine has a mass of 19amu. the total 3 of p+ and n0 in its nucleus is

19 (atomic mass-#p+= n0)

what is the electron configuration order?

2-8-18-32

which e- config could represent a strontium atom in an excited state?

2-8-18-7-3

The % by mass of carbon in HC2H3O2=

24(total mass of H)/60(total mass) x 100

iso. atomic mass %abundance Si-28 27.89 92.22 Si-29 28.98 4.69 si-30 29.97 3.09 find the total # of neutrons in an atom of Si-29

29 (isotopes) -14 (p+) = 15 neutrons

Group 1

Alkali metals +1

if M represents an alkali metal, what is the formula for the compound formed by M and oxygen

M2O

at STP, which list of elements contains a solid, a liquid, and a gas

Ba Br2 B

Celsius to Fahrenheit

C=5/9(F-32)

a 1 mole sample of neon gas occupies a volume of 24.4L at 298K and 101.3 kilopascals. Calculate the density of this sample

D=m/v 20.18g (mm of neon)/22.4L =0.90g/L

Fahrenheit to Celsius

F=9/5C+32

diatomic elements

H, N, O, F, Cl, Br, I

which substance contains nonpolar covalent bonds?

H2

group 17

Halogens -1

Electronegativity

How strongly an atom attracts electrons; Flourine is the highest one

which formula represents lead (II) chromate

PbCrO4

Wave-Mechanical Model (Modern Atomic Theory)

Small, dense, nucleus positively charged nucleus surrounded by electrons moving in "electron cloud". "Orbitals" are areas where an electron with a certain amount of energy is most likely to be found.

Bohr Model

Small, dense, positively charged nucleus surrounded by electrons in circular orbits

experiments performed to reveal the structure of atoms led scientists to conclude that an atom's____

V is mainly unoccupied

matter that is composed of 2 or more different elements chemically combined in a fixed proportion is classified as

a compound

explain why xx does not represent a compound

a compound is a combination of 2 or more different elements, only 1 element is shown more like diatomic

Bronze contains 90 to 95% copper and 5 to 10% tin because these percentages can vary bronze is classified as

a mixture

what was concluded about the structure of the atom as the result of the gold foil experiment?

a positively charged nucleus is surrounded by mostly empty space

group 2

alkaline earth metals +2

a sample composed only of atoms having the same atomic number is classified as

an element

metalloids (semimetals)

an element that has both metallic and nonmetallic properties; B Si Ge As Sb Te Po

Which value of an element is calculated using both the mass and the relative abundance of each of the naturally occurring isotopes of this element?

atomic mass

across a period (4)

atomic radius decreases electronegativity increases 1st ionization energy increases metallic character decreases

down a group (5)

atomic radius increases electronegativity decreases 1st ionization energy decreases metallic character increases same chemical properties energy levels increase but V.e- stays the same

isotopes

atoms with equal number of p+ but diff. # of n0 (or diff. atomic mass)

percent error formula/ percent composition

experimental value-accepted value/accepted value x 100

theoretical/% yield formula

experimental/theo x 100

at room temperature, a mixture of sand and water can be separated by

filtration

in calcium atom in the ground state, e- that possess the least energy are located in the _____

first e- shell

go over all formulas and

go over percent yield, percent erro, excess, and limiting

which group on the PT contains elements that react with oxygen to form compounds with the general formula X2O?

group 1

Which group of atomic models is listed in historical order from the earliest to the most recent?

hard-sphere model, electron-shell model, wave-mechanical model

ionic substances have

high melting/ boiling points that form crystals, dissolve in water, and conduct electricity in solution and as liquids

a dilute, aqueous potassium nitrate solution is best classified as a

homogeneous mixture

what is a chemical property of hydrogen gas

hydrogen gas burns the air (substance changed)

the modern model of the atom shows that e- are

in orbitals

How do the energy and the most probable location of an electron in the third shell of an atom compare to the energy and the most probable location of an electron in the first shell of the same atom?

in the 3rd shell, an e- has more energy and is farther from the nucleus

an e- in an atom moves from the ground state to the excited state when the energy of the e-___

increases

ionization energy trend

increases up and to the right

write IUPAC name for Fe2O3

iron (III) oxide

electrons fill in energy levels and orbitals starting with one that requires_____and the increasing energy levels have the _______

least energy; most energy

When an e- returns from a higher state to a lower energy state, it emits a specific amount of energy usually in the from of_____

light (spectroscope- tool used to identify the bright light spectrum)

Br and Hr are the only 2 what?

liquids

covalent substances have

low melting/ boiling points and don't conduct electricity

the characteristics spectral lines of elements are caused when e- in an excited atom move from

lower to higher energy levels, absorbing energy

which statement describes a chemical property of the element magnesium?

magnesium reacts with an acid

a solid substance is an excellent conductor of electricity. the chemical bonds in this substnace are most likely

metallic because the valence electrons are mobile

elements to the left of the staircase are

metals easily oxidized lose e- good electrical conductors shiny malleable ductile low ionization and electronegativites

which substance can be decomposed by chemical means

methane

solid samples of the element phosphorus can be black, white or red in color. the variations in color are due to different

molecular structures

When an atom gains an electron it becomes (non-metals)

negative ion & radius increases

given the balanced reaction: H2SO4+2KOH-> K2SO4+2H2O what is this reaction

neutralization

which element at stp is sold and a good conductor of electricity

nickel

which element is a solid at STP and a good conductor of electricity

nickel

what does a pure substance look like?

no mixtures or combinations of different atoms/elements

how do the atomic radius and metallic properties of sodium compare to the atomic radius and metallic properties of phosphorus?

sodium has a larger atomic radius and more metallic

At STP, fluorine is a gas and bromine is a liquid because, compared to fluorine, bromine has

stronger molecular forces

The carbon atoms in graphite and the carbon atoms in diamond have different

structural arrangements

given the balanced equation for producing bromomethane: Br2+CH4->CH3Br+HBr identify the type of organic reaction

substitution

structural formulas show

the # of ea. type of atom as well as their physical arrangement

molecular formulas show

the actual # of atoms per element in a single molecule

a physical change results in they can be

the arrangement of existing particles in a substance; no new particles observed with senses or measured

In an investigation, dripless wax candle is massed an then lighted. As the candle burns, a small amount of liquid wax forms near the flame. After 10 minutes, the candle's flame is extinguished and the candle is allowed to cool. The cooled candle is massed. Identify 1 physical change that takes place in this.

the burning candle has heat and light the melting of the wax

In an investigation, dripless wax candle is massed an then lighted. As the candle burns, a small amount of liquid wax forms near the flame. After 10 minutes, the candle's flame is extinguished and the candle is allowed to cool. The cooled candle is massed. State 1 observation that indicates a chemical change occured.

the candle burns (combustion) melting vaporization solidification

a chemical change results in

the formation of different particles with changed properties; describe how the substance interacts with other substances

An atom is electrically neutral because

the numbers of protons and electrons are equal

polar molecules have an

uneven distribution of electrons and have + and - charged ends; water; dissolved by another polar substance

what makes a molecule not symmetrical? a polar covalent molecular bond looks___

unpaired electrons symmetrical

What do Lewis Dot Structures show?

valence electrons bonding

a 10g sample of which element has the smallest volume at STP

zinc