CHEM 121 Test 1 2 & 3
Select the element with the most negative electron affinity
F
Electron added to atomic orbitals of the same energy will remain unpaired with parallel spins until the sub shell is more than half filled is a statement of
Hunds rule
An acid
donates protons in a proton transfer reaction
A system delivers 225 J of heat to the surroundings while delivering 645 J of work. Calculate the change in the energy of the system <>E
-870J
Hydrogen gas exerts a preasure of 466 torr in container. What is this pressure in atmospheres
0.613 atm
How many moles of ions are released when 0.27 moles of cobalt (II), CoCl2 is dissolved in water ?
0.81 mol
A flask has a mass of 78.23 g when empty and 593.63 g when filled with water. When the same flask is filled with concentrated sulfuric acid, H2SO4, its mass is 1026.57 g. What is the density of concentrated sulfuric acid? (Assume water has a density of 1.00 g/cm3 at the temperature of the measurement.)
1.840 g/cm^3
Natural gas or methane is an important fuel. Combustion of one mole of methane release 802.3 kilojoules of energy. How much energy does that represent in kilocalories
1.92x10^2 kcal
Lithium Hydroxide is used in alkaline batteries. Calculate the molarity of a solution prepared by dissolving 1.495 moles of LiOH in enough water to give a final volume of 750ml.
1.99M
Household sugar sucrose has the molecular formula C12H22O11. What is the % of carbon in sucrose by mass
42.1%
The mass of a sample is 550 milligrams. Which of the following expresses that mass in kilograms?
5.5 x 10^-4 Kg
Which measurement is expressed to 4 significant figures
62.40
Calcium fluoride CaF2 is a source of fluorine and is used to fluoridate drinking water.. Calculate its molar mass.
78.07 g/mol
Cold packs, whose temperatures are lowered when ammonium nitrate dissolves in water, are carried by athletic trainers when transporting ice is not possible. Which of the following is true of this reaction?
<>H>0, process is endothermic
Which of the following element has the largest atomic size?
Ba
Which scientist first proposed that the electron in the hydrogen atom can have only certain energies?
Bohr
Which one of the following substance when dissolved in water at equal molar concentration will give the solution with the lowest electrical conductivity?
C6H12O6(glucose )
Which one of the following ionic compounds is insoluble in water?
CaCO3
"The volume of an ideal gas is directly proportional to its absolute temperature at constant pressure and number of moles" is a statement of _______law.
Charles
Which of the following element has the largest first ionization energy?
Cl
Which of the following compound is ionic
MgCl2
Which of the following compound is covalent
PCl3
Select the arrangement of the electromagnetic radiation which starts with the lowest energy and increases to greatest energy
Radio, infrared, ultraviolet, gamma rays
What if any are the spectator ions when aqueous solution of HBr and RbOH n neutralize each other?
Rb+ and Br-
Who developed an empirical equation from which the wavelengths of the spectrum of hydrogen atoms can be calculated?
Rydberg
What is the chemical symbol for the group 6A (16) element that lies in period 4?
Se
Which of the following elements will form a cation a+2 charge
Sr
Which of the following is a metal ?
Thallium, TI, Z=81
Select the statement which does NOT apply to an ideal gas.
There are strong repulsive forces between the gas molecules
When an atom is represented by a symbol AZX the value of A is the
Total number of protons and neutrons in the atom
The difference between a student experimental experiment of the density of sodium chloride and the known density of this compound reflect the ________ of the students results
accuracy
in the modern periodic table the order in which the element are placed is based on
atomic number
Which of the following is a chemical change?
broiling a steak on a grill
Which of the following gases will be the slowest to diffuse through a room?
carbon dioxide,CO2
After an atom has lost an electron it becomes a/an ________ and has a ______charge
cation, postive
The interference pattern seen when light passes through narrow closely spaced slits is due to
diffraction
Millikan Oil Drop
established the charge on a electron
In a redo reaction electrons and transferred
from the substance being oxidized to the substance being reduced
A column of the periodic table is called
group
Which of the following activities is not part of good science
indulging in speculation
The symbol for the SI base unit of mass is
kg
The SI unit of speed velocity is
m/s
A system that does not work but which transfers heat to the surroundings has
q<0,<>E<0
Select the classification for the following reaction. 2Na(s)+2H20(I)->2NaOH(aq)+H2(g0
redox
Each electron in an atom must have its own unique set of quantum number is a statement of
the Pauli exclusion principle
The size of an atomic orbital is associated with
the principle quantum number
