Chem 121 FInal
What is the pressure today 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
How many moles of CO2 are produced when 2.5 moles of O2 react according to the following equation? C3H5+5O2-->3CO2+4H2O
1.5
prepared by dissolving .750 mol CaCl2 in enough water to make 0.500L
1.50 M
an imaginary element X consists of two isotopes having masses of 141 amu and 143 amu. A sample of X what found to contain 20% of the 141X isotope and 80% of the 143X isotope. 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?
15.0 mL
The number of grams in 7.0 moles of N2 is
196
How many grams of NaOH are needed to make 750mL of a 2.5% (w/v) solution?
19g
what is the electron configuration of S?
1s2 2s2 2p6 3s2 3p4
When the reaction shown is correctly balanced, the coefficients are, _______HBr + +______Ca(OH)2 ---> _____CaBr2 + _____H2O
2,1,1,2
Which of the following pH's corresponds to a strongly to acidic solution?
2.1
How many moles of NaHCO3 are present in a 2.0g sample?
2.38x10^-2
if the concentration of H30+ is 3.5x10^-3 M, the concentration of OH- is _____ M.
2.9x10^-12
How many mL of 16M NH3are needed to prepare 2.00L of a 2.00 M solution?
250mL
consider the balanced equation shown and identify the statement that is not true. Na2SO4(aq) + BaCl2(aq) ---> 2Nacl(aq) + BaSO4(s)
2NaCl could also be written as Na2Cl2
what is the density of a substance with a volume of V=26.2cm3 and a mass of m=94.9g?
3.62g/cm3
which measurement represents the smallest quantity?
3740nm
The [H3O+] in a solution with pH=6.35 is
4.5x10^-7 M
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?
405 mL
How many mL of 0.105 M AgNO3 are needed for an experiment that requires 0.00510 mol of AgNO3?
48.6mL
A sample of helium has a volume of 480 mL at 47.0°C and 740 mm Hg. The temperature is lowered to 22.0°C and the pressure to 625 mm Hg. What is the new volume?
524 mL
the molar mass of butane, C4H10, is ____ grams.
58.12
How many electrons can the occupy 2p subshell?
6
find the difference between two masses measured as 146.5g and 139.983g.
6.5g
a thimble of water contains 4.0x10^21 molecules. The number of moles of H2O is
6.6x10^-3
Consider the reaction shown: N2 + O2 → 2 NO ΔH = +43.2 kcal When 50.0 g of N2 react, ________ kcal will be ________.
77.1; consumed
Xylene a compound with the formula C8H10 is composed of
8 carbon atoms and 10 hydrogen atoms
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 30.0 ºC and 0.900 atm.
96.7 L
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
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 the following is a non-metal?
Cl
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 boiling point: H2, NH3, CCl4, H2Se
H2 < CCl4 < H2Se < NH3
which of the following structures is likely to exist?
H2CO
which reaction is an example of an acid base reaction?
H2SO4(aq)+Ca(OH)2(aq) ---> CaSO4(aq) +2H2O(l)
which of the following is the strongest acid?
H3PO4 (Ka=7.5x10^-3
What element is most likely to have chemical properties similar to those of bromine?
I
Which of the following is not soluble in water?
Iron(III) Hydroxide
which pair of elements is most likely to form an ionic compound
K and Br
the Spectator ions in the reaction shown are 2AgNO3(aq)+K2SO4(aq) --> 2NO3(aq)+Ag2SO4(s)
K+, NO3-
which of the following is a strong base?
KOH
which symbol does not denote a compound?
Kr
What are the strongest intermolecular forces between C5H12 molecules?
London dispersion forces
which of the following elements is most likely to form an ion with a +2 charge?
Mg
Which one of the following will act as a strong electrolyte in an aqueous solution
NH3
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?
NaCl will flow from B to A
of the following substances, which would form a basic solution when dissolved in water NH4Cl, Ba(NO3)2, K2CO3, NaF
NaF, K2CO3
In the reaction shown, _____ is oxidized and becomes ______. Ni(s)+CuCl(aq) ---> Cu(s)+NiCl2(aq)
Ni, Ni+
which of the following would be miscible with carbon tetrafluoride, CF4?
O2
which of the following compounds can be most accurately described as a covalent molecule?
PF3
what is the formula for the phosphate ion
PO4^3-
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.
although noble gasses do not normally form covalent compounds, XeO3, has been prepared. the systematic name of the compound is
Xenon trioxide
Write the equilibrium expression for the following reaction: 2 BrF5(g) ⇄ Br2(g) + 5 F2(g)
[Br2][F2]5/[BrF5]2
Which of the following contains potential energy?
a book on a table
an increase in solution pH corresponds to
a decrease in hydronium ion concentration and an increase in hydroxide ion concentration
A necessary requirement for a bronsted-lowry base is
a lone pair of electrons in its lewis dot structure
identify the reactants in the following reaction, calcium carbonate --> calcium oxide + carbon dioxide
calcium carbonate
All of the statements regarding "ΔH" are correct except it
can be called the entropy change.
A positively charged particle formed by the loss of one or more electrons from an atom is called a
cation
the name of Cl- is
chloride ion
table salt NaCl is a _______ and is found in the ______ phase
compound, solid
Adding one neutron to the nucleus of an atom
converts it to an isotope of the same element
Which change to the system below would cause equilibrium to shift to the right? 4 NH3(g) + 3 O2(g) ⇄ 2 N2(g) + 6 H2O(g) ΔH = -1531 kJ
decreasing the concentration of oxygen
In the reaction A + B → AB, which of the following will not increase the rate?
decreasing the temperature
In the reaction energy diagrams shown below, the reaction on the left is ___________, and it occurs ___________ the reaction on the right.
exergonic; faster than
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
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
a molecule in which the central atom forms two single bonds and has two lone pairs is said to have a _______ shape
linear
which group contains only elements which normally exist as diatomic molecules?
nitrogen, oxegen, fluorine
The classification of an acid or a base as weak or strong is determined by
none of the above
water can be dissolved in which type of compounds?
polar and ionic compounds
For the process of vaporization, the sign of ΔH is _________ and the sign of ΔS is _________.
positive, positive
Protons possess a ________ charge, and neutrons possess a ________ charge.
positive, zero
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
A chemical bond formed when two atoms share one pair of electrons is a _______ bond; it is best described as _____.
single, covalent
Which of the following can affect the activation energy (Eact) of a reaction?
use of a catalyst
Which description best fits a gas?
volume and shape of container; no intermolecular attractions
which is not an example of a solution?
whole milk
adding solute to a solution will increase which of the following
boiling point and osmotic pressure
which solution has the greatest osmolarity?
0.1 M AlCl3
In a precipitation the precipitate can be identified by the symbol
(s)
which of the following has three sig figs?
0.0250
The [OH-] and the pOH of 0.035 M KOH are, respectively,
0.035 M and 1.46
Which statement about solubility is not true?
additional solute added to a saturated solution will fully dissolve