140 terms

PHYS 1415 (Unit 3) Ch 14-17

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Chemistry is the study of
matter AND tranformations of matter
An example of basic research is
the study of the compostion of the atom
Of the trhree sciences, physics, chemistry, and biology, the most complex is
biology because it is based upon both the laws of chemistry and physics
If someone is able to explain an idea to you using small familiar words, what does this say about how well that person understands the idea?
a person who completely understands an idea is capable of explaining it using language that is familiar to both of you
Which of the following can be classified as matter?
all of the above

(ice cream, water, sand, perfume)
How would you describe the volume of the following object: the amount of water in a swimming pool
macroscopic
Which would have the most kinetic energy?
hot gas
What type of phase change does the following figure best describe?
. . . . . .
. . . . . .
........ . . . . . .
........ . . . . . .
evaporation
What type of phase change does the following figure best describe?

....... . . . . . . .
....... . . . . . . .
melting
Using the images illustrating identical volumes of different materials, which has the highest density?

............. . . . . . . . . . . . .
............. . . . . . . . . .
............. . . . . . . . . . . .
A B C
A
What state of matter does this diagram of submicroscopic particles represent?

. . . .
. . .
........
......
....
solid-gas mixture
The diagram on the far left shows the moving particles of a gaseous material within a rigid container. Which of the three boxes on the right best represents this material upon the addition of heat
box (b) because it shows the gas particles moving faster
The diagram on the left shows the interface of solid and liquid phases of a single substance. Which box best represents if heat were added? If heat were taken away?

...... . . . . . .......... . . . . . . . .
...... . . . . . .......... . . . . . . . .
...... . . . . . .......... . . . . . . . .
A B C
C - heat added
B - heat taken away
What is the gas found within a bubble of boiling water?
water vapor
Which of the following would be considered a physical property?
density
Which of the following would NOT be considered a chemical property?
the temperature at which liquid will boil
Which of the following elements should exhibit some metallic and some non-metallic properties?
Si
From the diagram, at which point is water boiling
A (top right)
From the diagram which is more dense: liquid xenon or solid xenon?
solid
The following image describes what type of change?
a chemical change (because the atoms are connected differently)
The following image describes what type of change?

.......... . . . . . . . . . .
.......... . . . . . . .
.......... . . . . . . . .
a physical change (because change only in position, not change in molecular structure)
Is the following transformation representative of a physical change or a chemical change?

+= ++
=+ ==
chemical change because the atoms are connected differently
How many atoms are in one molecule of Na2SO4?
7
How many different elements are in the compound C6H12O6?
3
If both are at the same temp, which box contains a higher boiling point liquid?

== == ++ == ==
++ == == += +=
== ++ == += +=
A B
box b - because form indicates liquid phase, plus it's a compound (different types of atoms)
Which substance has a lower boiling point?
molecule A because it is the first to transform into a liquid
What is a diatomic molecule?
a molecule that is composed of two atoms
What is the name of the following compound - CaCl2
calcium chloride
What is the name of the following compound - CO2
carbon dioxide
What is the name of the following compound - SF3
sulfur triflouride
Which of the following elements is diatomic in its natural state?
bromine
What is a valence shell
the outermost shell of electrons in an atom
Which of the following is the correct electron dot structure for cholorine (atomic no. = 17)
. .

: Cl .
. .
Which of the following has the greatest number of nonbonding pairs of electrons?
F
How many valence electrons does gallium (GA, atomic no = 31) have?
3
How many valence electrons does bromine (Br, atomic no = 35) have?
7
What is the role of unpaired valance electrons?
they take part in the formation of different types of bonds
How many more electrons can fit within the valence shell of a hydrogen atom?
1
The neon atom tends NOT to gain any additional electrons because
there is no more room available in its outermost occupied shell
If an element has a -1 charge and the following chemical symbol, how many electrons does it have?

19
F
9
10
If a neutral atom loses one electron, what is the electrical charge of the atom?
+1
If a neutral atom gains two electrons, what is the electrical charge of the atom?
-2
Which of the following is a positive ion?
Na+
Which of the following would be an ion with a double positive charge?
an Mg atom that loses two electrons
Which of the following elements will most likely form an ion with a +1 charge
Na
Which of the following elements will most likely form an ion with a -1 charge
Cl
What is the name for the following polyatomic ion - CH3CO2-1
acetate
Take money away from your bank account and the bank will show a negative credit. Take an electron away from and atom, however, and the atom shows up positive. Explain
Neutral atoms contain identically charged but oppositely signed protons and electrons. Removing one of the negative electrons results in an excess of positively charged protons
If the following generic atom were to undergo ionization, what would be the charge of the most likely product?.

X
+2
If the following generic atom were to undergo ionization, what would the most likely product be?

. .

: X :
. .
would probably not ionize

(tend not to form ions because valence shell already filled to capacity)
Which of the following molecules contains an ionic bond?
MgCl2

(ionic bond characterized by a metal & non-metal polyatomic ion)
How many chloride ions (Cl-1) are needed to balance the positive charge of a barium ion (Ba+2)
2
If you mix a typical aluminum ion (Al, atomic no = 13) with a typical oxygen ion (O, atomic no = 8), what compound is formed?
Al2O3
Which of the following substances contains F- ions?
CaF2

(Ca=2+, F=-1)
Barium ions carry a 2+ charge, and nitrogen ions carry a 3- charge. What would be the chemical formula for the ionic compound barium nitride?
Ba3 N2
Which are closer together: the two nuclei within potassium fluoride, KF, or the two nuclei within molecular fluorine, F2?
F2
Which of the following describes the reason for the following application of metals: structural supports for buildings
are strong but can be bent
What property of metal atoms account for many of the observed bulk phenomena seen in metal samples?
metal atoms easily lose one or more outer electrons
What property of alloys make them ideal for developing new materials?
the characteristics of the material change depending on how much of each component is present
If the concentration of gold in seawater is 2.0 milligram per ton of sea water and the mass of the ocean is 1.5 x 10^18 tons, how much gold is in the ocean?
3.0 x 10^12 kg
What is the main difference between an ionic and a covalent bond?
one is the sharing of a pair of electrons, the other is the transfer of at least one electron
How many covalent bonds would the following generic atom usually form?
. .
: X :
. .
would not usually form any covalent bonds
Which of the following is a covalent compound composed of nonpolar covalent bonds?
H2
What drives an atom to form a covalent bond: its nuclear charge or the need to have a filled outer shell
its nuclear charge
Phosphine is a covalent compound of phosphorus, P, and hydrogen, H. What is its chemical formula?
PH3
How many electrons are used to draw the electron-dot structure for acetylene, a covalent compound with the formula, C2H2
10
Which of the following molecules contains a polar bond?
H-F
Which of the following bonds would be the least polar?
C-H
Which of the following molecules is polar?
H F
C=C
H F
Which bond is most polar?
O-H
Which of the following is the strongest form of interatomic attraction?
a chemical bond
The separation of charges within a polar molecule is called a
dipole
Which of the following is the main form of intermolecular attraction in a water molecule?
hydrogen bonding
Which of the following molecules is most likely to show a hydrogen bonding interaction?
CH3 OH
Which of the following would have the lowest melting point?
CF4
Which of the following is a mixture?
air
The following image represents which kind of matter?

* ## ## * ##
## * ## * ##
** ## * ## ## ** ## **
a mixture
Each circle represents an atom. Which of the following boxes contains an element? A compound? A mixture
# ## # #* # # ** * ## *# #* #* #* ** * *
## # # #* # # ** * *# *# #* #* #* ** * *
Mixture Compound Element
Why cant the elements of a compound be separated from one another by physical means?
their atoms are too tightly bound to one another
Which box represents a compound?
#* # ###* #*#*
#* #* # # #* #* #*
#* #* # # #* #* #*
C only
Many dry cereals are fortified with iron, which is added to the cereal in the form of small iron particles. How might these particles be separated from the cereal?
collect the iron fillings with a magnet
Which of the following would be considered a heterogeneous mixture?
salad dressing
How would you classify the following material - milk
a suspension
How would you classify the following material - coffee (with milk)
a suspension
A sample of water that is 99.9999 % pure contains 0.0001% impurities. Consider that a glass of water contains on the order of a trillion trillion (1 x 10^24) molecules. If 0.0001% of these molecules were the molecules of some impurity, about how many impuritiy molecules would this be?
1,000,000,000,000,000,000 (one million trillion: 1 x 10^18)
Someone argues that he or she doesnt drink tap water because it contains thousands of molecules of some impurity in each glass. How would you respond in defense of the waters purity, if it indeed does contain 1000's of molecules of some impurity per glass?
compared to the billions and billions of water molecules, a thousand molecules of something else is practically nothing
Which of the following boxes represents a suspension?
definition of suspension = a homogenous mixture in which the various components are in different phases
The same amount of red colored Kook-aid crystals are added to a still glass of thick sugar water and a still glass of distilled water. Both are the same temp. Neither is stirred. Which should become uniform in color first?
the glass of distilled water
A sample of steel is composed of 5% carbon and 95% iron. Which is the solvent?
iron
Which of the following solutions is the most concentrated?
one liter of water with 10 grams of sugar
Which of the following solution is the most concentrated?
0.5 liter of water with 50 grams of sugar
How many molecules of sucrose are in a 0.5 moles of sucrose?
3.01 x 10^23 molecules of sucrose
What is the molarity of 0.5 liters of a solution with 5 miles of sucrose in it?
10 molar
What is the molarity when water is added to 2 moles of sodium chloride to make 0.5 liter of solution?
4 M
How are interatomic forces and solubility related?
solubility depends on the solvents ability to overcome the intermolecular forces in a solid
Which of the following might have the lowest solubility in water?
CH3 CH3
A solid has a solubility at room temp of 78 grams per liter. If 1.0 L of a hot solution containing 100 g of solute is cooled to room temp, how much solid is formed?
22 g
If the solubility of a compound is 30 grams per liter, how much solid is left undissolved if you mix 30 g of the compound in 0.33 L of solution?
20 g
The boiling point of 1,4-butanediol is 230*C. Would you expect this compound to be soluble or insoluble in room temp water?
water would be attracted to both ends, and is infinitely soluble in water
Which solute graphed above has a solubility in water that does not markedly increase with increasing temp?
Na Cl
Account for the observation that ethyl alcohol, C2 H5 OH, dissolves readily in water but dimethyl ether, CH3 OCH3, which has the same number and kinds of atoms, does not
because dimethyl ether lacks an OH group, it is significantly less polar than is ethyl alcohol and is not readily soluble in water
Fish dont live very long in water that has just been boiled and brought back to room temp. Suggest why.
the boiling process removes the air that was dissolved in the water. Upon cooling the water is void of its usual air content, hence, the fish drown
Which of the following might best describe a soap or detergent?
^-^-^-^-O
Which of the following might best describe the product obtained from soap and hard water (soap scum)
^-^-^-O-^-^-^
Which of the following might best describe the product obtained from soap and hard water (soap scum)
^-^-^-O-^-^-^
Why do hot water heaters lose their efficiency quicker in households with hard water?
the calcium carbonate on the inner surface of the hot water tank builds up to the point that it insulates the water from the heating element
Which of the following in not a typical use for potable water?
irrigation
Allowing water to cascade or bubble in a fountain during the purification process is an example of
a gas dissolving in a liquid
Why is a large quantity of water used in industrial processes in the US purified by desalinization?
the sources are brackish or metal ion rich
During osmosis
the water moves into the concentrated solution faster than it leaves
Which of the following would cost the least to purify by reverse osmosis?
agricultural runoff
Why do red blood cells, which contain an aqueous solution of dissolved ions and minerals, burst when placed in fresh water?
the fresh water acts to dissolve the blood cell wall
Which of the following statements about sewage is NOT true
all municipalities must treat sewage the same way
How do advanced integrated ponds for waste water treatment take advantage of solar energy?
by letting plants use it to consume waste
The measure of the amount of oxygen consumed by certain bacteria is the ______, which is also a measure of the dissolved organic material
biochemical oxygen demand
What is wrong with the following depiction of a chemical reaction?

== == === === ===
== == === === ===
All the above
-one box contains more molecules than the other
-these boxes contain only molecules but no atoms
-one box contains more atoms than the other
What is a chemical equation?
a shorthand notation for illustrating a chemical reaction
Given the following generic chemical reaction, which is the reactant?

X ---> Y
X is the reactant
For the following balanced reaction, which of the following is a gas?
Cl2
Balance the following chemical equation

____N2 + ____H2 ----> ____NH3
1, 3, 2
What coefficients balance the following equation?

____P4(s) + ____H2(g) ---> ____PH3(g)
1, 6, 4
What coefficient is needed in front of the O2 molecule to balance the following equation?

2C4 H10(g) + ____O2(g) ---> 8CO2(g) + 10H2O(l)
13
The reactants shown schematically below represent iron oxide, Fe2 O3, and carbon monoxide, CO. Which of the following is the correct full balanced chemical equation for what is depicted?
Fe2 O3 + 3CO ---> 2 Fe + 3CO2
If you heat 50 grams of wood and produce 10 g of ash, what is the total mass of the product?
more than 50 g
Which has more atoms: a 1-gram sample of carbon 12 or a 1-gram sample of carbon 13?
a 1-gram sample of carbon 12
How many moles of sugar, C12 H22 O11, are there in 200 grams
0.585 moles
If the relative mass of a ping pong ball is 1/20 that of a golf ball, how many ping pong balls would you need to equal the mass of two golf balls?
40
If the relative mass of a hydrogen atom is 1/4 that of a helium atom, how many helium atoms would you need to equal the mass of 200 hydrogen atoms
50
What is the formula mass of a molecule of C6 H12 O6?
180
What is the mass of one mole of H2?
2 g
According to the following balanced chemical equation, if you want to generate two moles of H2O, how many molecules of O2 do you need?
6.022 x 10^23
What is the number of moles of H2O produced if you combust 0.5 mole of CH4 according to the following balanced equation?
1 mole
What is the number of moles of H2O produced if you combust 0.5 mole of CH4 according to the following balanced equation?

CH4 + 2O2 ---> CO2 + 2H2O
1.204 x 10^24 molecules
Which has more atoms: 64.058 g of sufur dioxide, SO2 (64.058 amu), or 72.922 g of hydrogen chloride, HCI (36.461amu)?
72.922 g of HCI has more atoms than 64.058 g of SO2
Two amu equals how many grams?
3.322 x 10^-24 grams
What is the mass of a water molecule, H2O, in grams
2.99 x 10^-23 grams
How many grams of gallium are there in a 145 gram sample of gallium arenside, GaAs?
69.7 g
Small samples of oxygen gas needed in the laboratory can be generated by any number of simple chemical reactions, such as: 2 KCIO3(s) ---> 2 KCI(s) + 3 O2(g). What mass of oxygen (in grams) is produced when 122.55 g of KCIO3 (formula mass = 122.55 amu) takes part in this reactions?
48 grams
How many moles of water, H2O, are produced from the reaction of 16 grams methane, CH4, with an unlimited supply of oxygen, O2? How many grams of H2O is this?
2.0 moles of water, which is 36 grams
Steel wool wetted with vinegar is sealed within a balloon inflated with air. After several hours, what happens to the volume of the balloon?
the balloon deflates