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141 terms

Chem Exam 2

STUDY
PLAY
Knowledge about what products are produced in a chemical reaction is obtained by...
labratory analysis
A chemical reaction has NOT occured if the products have...
the same chemical properties as the reactants
Which observation does NOT indicate that a chemical reaction has occured?
Change in total mass of substances
The word equation for the formula equations shown is {C2H5OH+O2->CO2+H2O+energy}
ethanol+oxygen->carbon dioxide+water+energy
The word equation solid carbon+oxygen gas->carbon dioxide gas+energy, represents a chemical reaction because...
CO2 has chemical properties that differ from those of C and O
In the unbalanced equation for the formula equation CO+O2->CO2+energy, energy...
is released
The state of matter for a reactant or a product in a chemical equation is indicated by a...
symbol after the formula
An insoluble solid produced by a chemical reaction in solution is called...
a precipate
How would oxygen be represented in the formula equation for the reaction of methan and oxygen to yield carbon dioxide and water?
O2
The products of the reaction, C2H5OH+3O2->2CO2+3H2O have the same ____ as the reactants.
atoms
After the correct formula for a reactant in an equation has been written, the...
formula should not be changed.
To balance a chemical equations, it may not be necessary to adjust the...
coefficients
A chemical equation is balanced when the...
same number of each kind of atom appears in the reactants and in the products.
After the first steps in writing an equation, the equation is balanced by...
adjusting the coefficients to the smalled whole-number ratio.
What is the balanced equation when aluminum reacts with copper{II} sulfate?
2Al+3CuSO4->Al2(SO4)3+3Cu
Which coefficients correctly balance the formula equation CaCO3->CaO+COx2
1,1,1
Is the equation 2H2+O2->H2O balanced?
No
Which coefficients correctly balance the formula equation NH4NO2->N2+H2O?
1,1,2
Which coefficients correctly balance the formula equation CaO+H2O->Ca(OH)2
1,1,1
Which coefficients correctly balance the formula equation Zn(OH)2+CH3COOH->Zn(CH3COO)2+H2O
1,2,1,2
A reaction of a hydrocarbon, in which carbon dioxide and water are produced, is classified as a...
combustion reaction
In what kind of reaction do two or more substanecs combine to form a new compound?
synthesis
The equation A+X->AX is the general equation for a...
synthesis reaction
In what kind of reaction does a single compound produce two or more simpler substances?
decomp. reaction
The reaction 2KClO3->2KCl+3O2 is a...
decomp. reaction
In what kind of reaction does one element replace a similar element in a compound?
displacement reaction
The equation A+BX->AX+B is the general equation for a...
displacement reaction
The reaction Cl2+2KBr->2KCl+Br2 is a...
displacement reaction
A balanced chemical equation allows one to determine the...
mole ratio of any two substances in the reaction.
The coefficients in a chemical equation represent the...
relative numbers of moles of reactants and products.
How many mole ratios can be correctly obtained from the chemical equation 2NO->N2+O2?
6
In the reaction Ca+Cl2->CaCl2, what is the mole ratio of chlorine to calcium chloride?
1:1
In the reaction N2+3H2->2NH3, what is the mole ratio of nitrogen to ammonia?
1:2
In the reaction 2H2+O2->2H2O, what is the mole ratio of oxygen to water?
1:2
What is the mole ratio of oxygen to phosphorus {V} oxide in the reaction P4+5O2->P4O10?
5:1
In the chemical equation wA+xB->yC+zD, if one knows the mass of A and the molar masses of A,B,C,&D, one can determine...
the mass of any reactants or products.
If one know the mass and molar mass of reactant A, and the molar mass of product D in a chemical reaction, one can determine the mass of product D by using the...
estimating bond energies involved in the reaction.
What is needed to calculate the mass of ammonia gas produced from 2L of nitrogen gas in excess hydrogen gas in the reaction below? {N2+3H2->2NH3}
One molar mass, and two mole ratios
A chemical reaction involving substances A and B stops when B is completely used. B is the...
limiting reactant
The substance that restricts the participation of other reactants in a chemical reactionis known as the...
limiting reactant
The substance not completely used up in a chemical reaction is known as the...
excess reactant
To determine the limiting reactant in a chemical reaction, one must know the...
availible amount of each reactant.
What is the ratio of the actual yield to the theoretical yield, multiplied by 100%?
percentage yield
What is the measured amount of a products obtained from a chemical reaction?
actual yield
Actual yield must be determined by...
experiments
The actual yield of a chemical reaction is...
less than the theoretical yield.
All of the following are heterogeneous mixtures excentp... {whole wheat bread, granite, tap water, an oil-water mixture}
tap water
Which of the following expresses concentration? {molality, molarity, parts per million, all}
all of the above
What is the molarity of a solution that contains .202 mil KCl in 7.98L of solution?
.202/7.98=.0253M
Dissolved in water to make 100mL of solution, 1g of NaCl would have a concentration of...
.171M
What is the molarity of a solution that contains 125g NaCl in 4L solution?
.535M
How many moles of HCl are present in .7L of a .33M HCl?
.23mol
An NaOH soultion contains 1.9mol of NaOH, and its concentration is .555M. What is its volume?
3.42L
Which of the following is an electrolyte? {sodium chloride, sugar, water, glass}
sodium chloride
Which is a molecular substance whose water solution conducts electricity? {hydrogen chloride, liquid hydrogen, sugar, iron}
hydrogen chloride
Molecules whose water solutions conduct current...
ionize in water
A dissolved solute that does not form ions is...
a nonelectrolyte
Acids taste...
sour
Strong acids are...
strong electrolytes.
Strong bases are...
stron electrolytes
Whose definition of acids and bases emphasizes the role of protons?
Bronsted and Lowry
What is the pH of a neutral solution at 25*C?
7
A water solution whose pH is 10...
is always basic.
The pH of a solution is 9. What is its H3O concentration?
1X10^-9M
The pH of a solution is 10. What is its OH concentration?
1X10^-4M
What is the pH of a 1X10^4M Hcl solution?
4
What is the pH of a 1X10^-5M KOH solution?
9
If [H3O]=1.7X10^-3M, what is the pH of the solution?
2.77
A water solution whose pH is 4...
is always acidic
What is the pH of a solution whose hydronium ion concentration is 5.03X10^-1M?
.298
The pH range over which an indicatory changes color is its...
transition interval
In nuclear chemistry, a nucleon is a...
neutron and proton
A nuclide is a...
nucleus of an atom with a specific number of protons and neutrons
A nuclide is identified by...
the number of protons and neutrons in its nucleus
A nuclide is represented by...
the symbol of the element preceded by a superscript indicating its mass number and a subscript indicating its atomic number, and the full name of the element followed by a hyphen and the mass number
What does th 4 in {4{top}2{bottom}}He represent?
the mass number
What does the 101 in {256{top}101{bottom}}Md represent?
the atomic number
What does the 218 in polonium-218 represent?
the mass number
Mass defect is the difference between the...
sum of the masses of the separate nucleons and the mass of the nuclide.
In a nuclear reaction, unstable nuclei that change their number of protons and neutrons,
give off large amounts of energy, and increase their stability.
The energy released in a nuclear reaction comes from...
the binding energy of the nucleus
List nuclear radiation from most massive to least massive...
alpha, beta, gamma
Which of the following particles has the same mass as an electron but is a positive charge and is sometimes emitted from the nucleus during radioactive decay?
positron
Which series consists of radioactive nuclides produced by successive radioactive decay until a stable nuclide is reached?
nuclide series
If the particle that starts a nuclear reaction is also one of the products, the process is a...
chain reaction
The half-life of an isotope is the time required for half the nuclei in a sample of the isotope to...
undergo radioactive decay
Each radioactive nuclide has its own...
half life
uranium-235 absorbing a neutron and splitting into barium-141, krypton-92, and three neutrons is an example of...
fission
barium-141, krypton-92, and three nutrons combining to form uranium-235 is an example of...
fusion
How many half-lives are required for 3/4 of the nuclei of an isotope in a sample to decay?
2
What is the half-life of an isotope if 125g of a 500g sample of the isotope remains after 3 years?
1.5 years
To use radioactive dating for a substance, you must know the substance's...
half-life
What unit is used to measure radiation damage to human tissue?
rem
How do radioactive nuclides affect photographic film wrapped in lightproof paper?
they fog the film
In writing a formula equation for a reaction that produces hydrogen gas, the correct representation of hydrogen gas is ____.
H2
A catalyst for a reaction is indicated by a ________ written over the arrow in a chemical equation.
chemical formula
The mass of the products of the reaction C2H5OH+3O2->2CO2+3H2O equals the mass of the reactants because the products are made up of the same ____ as the reactants.
atoms
In an equation, the symbol for a substance in water is _____.
aq
In the chemical equation 2AlCl3{aq}+3Pb(NO3)2{aq}->3PbCl2{s}+2Al(NO3)3{aq}, the state of PbCl2 is a...
solid
In the chemical reaction 2Cr+3O2->2CrO3, two chromium atoms combine with ___ oxygen atoms.
6
The small whole number that appears in front of a formula in a chemical equation is called a....
coefficient
When the formula equation Fe3O4+Al->Al2O3+Fe is correctly balances, the coefficient of Fe is ____
9
When the formula equation H2+Cl2->HCl is correctly balanced, the coefficient of HCL is ___
2
The reaction 2Mg+O2->2MgO is classified as a ______ reaction.
synthesis
The equation AX->A+X is the general equation for a _____ reaction.
decomp.
When placed in water, a metal more active than hydrogen will form two substances, a metal hydroxide and ____ gas.
hydrogen
In a ________ reaction, ions of two compounds exchange places in aqueous solution to form new compounds.
double-displacement
The equation AX+BY->AY+BX is the general equation for a ______ reaction.
double-displacement
The ratios obtained from the coefficients of substances in a balanced chemical equations are called ______ because they can be used to convert moles of one substance to moles of another substance.
mole ratios
The unit of the following expression is ______. 100g H2O X {mol H2O/18.02g H2O}
moles H2O
The unit of the following expression is ____. 100g H2O X {1/molar mass H2O}
mol
The substance that controls the quantity of product than can be formed in a chemical reaction is the ______.
limiting reactor
The substance that is not used up completely in a chemical reaction is the _____.
excess reactant
The ratio of actual yield to theoretical yield X 100% is called the ______.
percentage yield
Almost all of the gas inside an inflated automobile safety air bag is molecular ____.
nitrogen
The function of the carburetor in a small internal combustion engine is to control the ratio of ____ to oxygen.
fuel
The proportions of the reactants and products involved in a chemical reaction are shown by the _____ in the balanced chemical equation describing the reaction.
coefficients
On a very small scale, the numbers of particles of each substance in a reaction are represented by the _____ in the balanced chemical equation describing the reaction.
coefficients
In the equation N2+3H2->2NH3, the ratio of 3:2 relates mol H2 to mol ____.
NH3
In the equation N2+3H2->2NH3, the mole ratio of N2 to H2 is _____.
1:3
The unit of the expression mol H2O X molar mass H2O is _____
gH2O
The expression below converts the quantity, mass HCl, to the quantity, _____. mass HCl X {1/molar mass HCl} X {1 mol Cl2/2mol HCl}
mol Cl2
If 2 moles of each reactant are available for the reaction described by the following equation, SiO2+3C->SiC+2CO, ______ is the substance that is the limiting reactant.
C
The eficiency of a reaction is described by the ____ yield.
percentage
A substance whose water solution conducts a current is an _____.
electrolyte
A substance that ionizes nearly completely in an aqueous solutions and produces H3O ions is a strong ____.
acid
H2SO4 is classified as a _____ acid.
strong
CH3COOH is classified as a ____ acid.
weak
A substance that ionizes nearly completely in aqueous solutions and produces OH ions is a strong ______.
base
A Bronsted-Lowry ____ is a proton donor.
acid
The pH scale in general uses ranges from _____
0-14
The pH of a basic solution is ____ than 7.
more/ greater
An acidic solution makes the color of pH paper turn ___.
red
A basic solution turns the color of pH paper turn ____.
blue
The process by which an unstable nucleus emits one or more particles, or energy in the form of electromagnetic radiation is called ______.
radioactivity
In a positron emission, the number of ____ and the number of ____ are each reduced by two in a nuclide.
protons and neutrons
The combination of the nuclei of small atoms to form a larger nucleus is called nuclear ____.
fusion
The critical mass is the minimum mass of a fissionable isotope that provides the number of neutrons needed to sustain a _____.
chain reaction
The splitting of the nucleus of a large atom into two or more fragments is called nuclear ____.
fission
Stars, including our sun, generate energy in the process called nuclear _____.
fusion
Smoke detectors use the ionization properties of a type of nuclear decay called ____ decay to detect changes in air caused by smoke particles.
alpha