Chemistry Final Exam
What is the pressure in atm if the weatherman says the current pressure today is 742 torr?
0.976 atm
How many moles of CO2 are produced when 2.5 moles of O2 react according to the following equation? C3H5 + 5 O2 ----- 3 CO2 + 4 H2O 1.5, 3, 5, 6, 18
1.5
How many moles of CO2 are produced when 2.5 moles of O2 react according to the following equation? C3H5 +5O2---- 3 CO2 + 4 H2O
1.5
What is the molarity of a solution prepared by dissolving 0.750 mol CaCl2 in enough water to make 0.500 L of solution? 0.375, 0.667, 1.50, 83.2, 166.5
1.50M
An imaginary element X consists of two isotopes having masses of 141.0 amu and 143.0 amu. A sample of X was found to contain 20% of the 141X isotope and 80% of the 143X. Calculate the atomic weight of X.
142.6 amu
How many mL of 0.360 M HNO3, are needed to neutralize a 22.5 mL sample of 0.240 M KOH 5.40, 15, 22.5, 33.8, 62.5
15.0 ml
Atoms of 35/17 Cl contain ________ protons and ________ electrons.
17;17
The number of grams in a 7.00 moles of N2 is 4.12x10^24, 14, 18, 98, 196
196
how many grams of NaOH are needed to make a 750 mL of a 2.5 % (w/v) solution?
19g
What is the electron configuration of S?
1s2 2s2 2p6 3s2 3p4
Consider the balanced equation shown and identify the statement that is not true. Na2SO4 + BaCl2 ---2NaCl + BaSO4
2 NaCl (aq) could be also correctly written as Na2Cl2 (aq)
Which of the following pHs corresponds to a strongly acidic solution?
2.1
In the reaction 2 C + O2 --- 2CO, how many moles of carbon are needed to produce 66 g of carbon monoxide? 0.424, 1.18, 2.36, 4.71, 28.3
2.36
How many moles of NaHCO3 are present in a 2.00 g sample? 2.38x10^-2, 1.27x10^-2, 2.00, 85.0, 168
2.38 x 10 ^ -2
If the concentration of H3O+ is 3.5 x 10 ^ -3 M, the concentration of OH- is ___M 2.9x10^-12, 1.0x10^-12, 1.0x10^-7, 3.5x10^11, 10.5x10^-3
2.9 x 10 ^-12
In a reaction to produce chlorine gas, the theoretical yield is 25.6 g. What is the actual yield of the reaction if the percent yield is 83.5%?
21.4 g
How many mL of 16 M NH3 are needed to prepare 2.0 L of a 2.0 M solution? 250, 125, 16, 8, 4
250 mL
When the reaction shown is correctly balanced, the coefficients are: ___ HBr + ____Ca(OH)2 ----- ____ CaBr2 + ____ H2O
2;1;1;2
What is the density of a substance with a volume of V=26.2 cm3 and a mass of m=94.9g?
3.62 g/cm3
Which measure represents the smallest quantity
3740 nm
The (H3O+) in a solution with ph= 6.35 is 7.65, 6.35, 4.5x10^-7, 0.80, 2.2x10^-8
4.5 x 10 ^-7
A sample of gas has a volume of 135 mL at 0.600 atm. What would be the volume if the pressure is decreased to 0.200 atm while temperature is held constant? 45, 101, 135, 180, 405
405 mL
How many mL of 0.105 M AgNO3 are needed for an experiment that requires 0.00510 mol of AgNO3? 0.536, 17.8, 18.70, 20.6, 48.6
48.6 mL
A sample of helium has a volume of 480 mL at 47 C and 740 mm Hg. The temperature is lowered to 22 C and the pressure to 625 mm Hg. What is the new volume?
524 mL
The molar mass for butane, C4H10, is _____ grams
58.12
How many electrons can occupy the 2p shell?
6
Find the difference between tow masses measured as 146.5 grams and 139.983 grams. Express the answer to the correct number of sig figs.
6.5 grams
A thimble of water contains 4.0 x 10 ^ 21 molecules. The number of moles of H2O is 2.4 x 10^45, 6.6x10^-3, 6.6 x10^-23, 2.4 x 10^23, 2.4 x 10 ^-23
6.6 x 10 ^ -3
Calculate the equilibrium constant for the reaction below if a tank was found to contain 0.355 M CO, 0.180 M O2, and 1.21 M CO2 2 CO + O2 --- 2 CO2 64.5, 22.9, 18.9, 5.23x10^-2, 1.55 x 10^-2
64.5
consider the reaction shown: N2 + O2 --- 2NO ^ H= 43.2 Kcal When 50.0 g of N2 react_____ kcal will be _____
77.1 consumed
What is 0.0970 written in scientific notation?
9.70 x 10^-2
Calculate the volume of a 3.50 mol sample of carbon dioxide at 30 C and 0.900 atm. 8.54 x10^-4, 2.20, 9.58, 96.7, 421
96.7 L
Which statement about solubility is not true
Additional solute added to a saturated solution will fully dissolve
Adding solute to a solution will increase which of the following?
Both A and C boiling point and osmotic pressure
An increase in solution pH corresponds to
Both B and C decrease in hydronium and increase in hydroxide
When a liquid sample is taken from sea level to a higher elevation, what happens to the external (atmospheric) pressure on the liquid and the boiling point of the liquid?
Both decrease
In the reaction below, the conjugate acid of CH3COO- is CH3COO- + H2CO3 ---- CH3COOH + HCO3-
CH3COOH
Which of the following structures is likely to exist?
COH2
What is the formula for the ionic compound formed between calcium and nitrate?
Ca(NO3)2
Which of the following is a non-metal?
Cl
Which of thew following is a non-metal?
Cl
In the reaction energy diagrams shown below, reaction A is ____ and it occurs ___ reaction B.
Exergonic; faster than
What is the typical net ionic equation for an acid-base neutralization of KOH and HCl?
H+ (aq) + OH- (aq) ---- H2O (l)
Rank the following in increasing order of increasing boiling point: H2, NH3, CCl4, H2Se
H2, CCl4, H2Se, NH3
Which reaction is an example of an acid-base reaction?
H2SO4 (aq) + Ca(OH)2 (aq) ----- CaSO4 (aq) + 2H2O (l)
Which one of the following is the strongest acid
H3PO4 ( K= 7.5 x 10 ^ -3)
Which element is most likely to have chemical properties similar to those of bromine?
I
According to Avogadro´s Law, the volume of a gas will _____ as the _____ is increased while the ____ are held constant.
Increase; number of moles; pressure and temperature
Which of the following is not soluble in water?
Iron(III) Hydroxide
Which pair of electrons is most likely to form an ionic compound if allowed to react together?
K and Br
The spectator ions in the reaction shown are 2 AgNO3 (aq) + K2SO4 (aq) ---- 2 KNO3 (aq) + Ag2SO4 (s)
K+ and NO3-
Which one of the following will act as a strong electrolyte in an aqueous solution?
KNO3
Which symbol does not denote a compound
Kr
Which of the following elements is most likely to form an ion with a +2 charge?
Mg
Which of the following is a strong base?
NH3
The following equation represents the formation of nitrogen dioxide, a major component of smog, 2 NO + O2 --- 2NO2 If 0.68 mole of NO is reacted with 0.79 mole of O2 to produce NO2, the limiting reactant is
NO
Of the following four substances, which would form a basic solution when dissolved in water NH4Cl, Ba(NO3)2, K2CO3, NaF
NaF and K2CO3
In the reaction shown, ____ is oxidized and becomes
Ni; Ni 2+
Which group contains only elements which normally exist as diatomic molecules?
Nitrogen;oxygen;fluorine
Which of the following would be miscible with carbon tetrafluoride, CF4?
O2
Which of the following is an example of a molecular solid?
PCl5
Which of the following compounds can be most accurately described as a covalent molecule?
PF3
What is the formula of the phosphate ion?
PO4 3-
Consider a pyramidal molecule, such as NH3, in which the central atom has one lone pair of electrons. The electronegativities of H and N are 2.1 and 3.0, respectively. Based on these values and on consideration of molecule geometry, the H-N bond is considered_______and the molecule is______ ELECTRONEGATIVITY DIFFERENCE BOND 0-0.4 nonpolar covalent 0.5-1.9 polar covalent 2.0 and above ionic
Polar polar
Which of the following conditions characterizes a system in a state of chemical equilibrium?
Reactants are being consumed at the same rate they are being produced
Which statement about the system is not true? 2 SO2 + O2 ----- 2 SO3 + heat K= 4.8 x 10 ^ 27
Removing O2 will cause an increase in the amount of SO3
Which of the following is the correct valence dot structure for silicon?
Si four around it
In forming covalent bonds where the octet rule is obeyed, oxygen usually forms bonds and fluorine usually forms bonds.
Two;one
If ¨A¨ contains 0.20 M NaCl and is separated by a semipermeable membrane from ¨B¨ which contains 1.0 M NaCl, which event will occur?
Water will flow from ¨A¨ to ¨B¨
Which is not an example of a solution?
Whole milk
Which of the following contains potential energy?
a book on a table
A necessary requirement for a Bronsted-Lowry base is
a lone pair of electrons in its Lewis dot structure
Water can be used to dissolve which type of compounds?
both B and C polar and ionic compounds
identify the reactant in the following reaction: Calcium carbonate--- calcium oxide + carbon dioxide
calcium carbonate
All of the statements regarding the symbol ¨^ H ¨ are correct except
can be called entropy
A positively charged particle formed by loss of one or more electrons from an atom is called
cation
The name of Cl- is
chloride ion
Table salt NaCl is an and if found in the phase.
compound; solid
Adding one neutron to the nucleus of an atom
converts it to an isotope of the same element or increases its mass number by one
which change to the system below would cause equilibrium to shift to the right? 4 NH3 + 3O2 --- 2 N2 + 6H2O ^H= -1531 kJ
decreasing the reaction temperature
In the reaction A+ B--- AB, which of the following will not increase the rate
decreasing the temperature
Xylene, a compound with the formula C8H10, is composed of
eight atoms of carbon and ten atoms of hydrogen
Main group elements that are non-metals usually one or more electrons to form which have a charge
gain;anions;negative
The amount of energy involved in melting a substance without changing its temperature is called the
heat of fusion
What are the strongest intermolecular forces between C5H12 molecules?
london dispersion forces
For the process of vaporization, the sign of ^H is _____ and the sign of ^S is _____
positive and positive
During the hydrolysis of water to form hydrogen and oxygen gases, there is an increase in entropy. This mean that the sign of ^S is _____ and that the randomness of the system ____
positive; increases
Protons possess a ________ charge, and neutrons possess a ________ charge.
positive; zero
A chemical bond formed when atoms share one pair of electrons is a bond; it is best described as
single;covalent
The classification of an acid or a base as weak or strong is determined by
the extent of dissociation of the dissolved acid or base
Which of the following can affect the activation energy of a reaction?
use of a catalyst
Which description best fits a gas?
volume and shape of container; no intermolecular attractions
Although noble gases do not normally form covalent compounds, XeO3 has been prepared. The systematic name of this compound is
xenon trioxide
Which solution has the greatest osmolarity?
0.1 M AlCl3
A molecule in which the central atom forms two single bonds and has two lone pairs is said to have a shape
bent
Write the equilibrium expression for the following reactions 2 BrF5 ---- Br2 + 5 F2
(Br2) (F2)5/ (BrF5)2
In a precipitation reaction the precipitate can be identified by the symbol
(s)
The (OH-) and the pOH of 0.035 M KOH are, respectivley,
0.0035 M and 1.46
Which of the following measurements has three sig figs
0.0250g