Chemistry Final
A scale is used to measure 5.98 g of magnesium chloride (MgCl2). How many moles of magnesium chloride were measured?
.0628 mol MgCl2
A sample of iron is determined to contain 3.50 x 1022 atoms of iron. How many moles of iron contained in the sample?
0.0581 moles Fe
Convert 21,400 cm to kilometers
0.214 km
Convert 540 mL to L
0.54 L
The mass of a sample of Na2O is measured to be 45.50 g. How many moles of Na2O are in the sample?
0.7341 mole
How many orbitals are on an s sublevel? How many electrons can an s sublevel hold?
1 orbital, 2 electrons
List the three intermolecular forces (IMFs) that we covered in class, and what causes each force.
1) London Dispersion Forces (LDFs) - caused by the motion of electrons 2) Dipole-Dipole Forces - caused by polar molecules 3) Hydrogen Bonding - caused by hydrogen being bonded to a highly electronegative atom (N, O, or F)
The chemical formula of xenon tetrafluoride is XeF4. A light bulb is filled with xenon tetrafluoride and found to contain 3.56 x 1024 atoms of fluorine. How many moles of XeF4 are in the light bulb?
1.48 moles
How many atoms of oxygen are present in a 5.65 g sample of beryllium carbonate (BeCO3)?
1.48 x 10^23 atoms
Find the density of a material, given that a 5.03 g sample occupies 3.24 mL.
1.55 g/mL
A liquid is measured and found to have a density of 0.890 g/mL. If an 11.6 mL sample of the liquid is obtained, what would the mass of the sample be?
10.3 g
Solve and give answers in the correct number of significant figures: 12.011 - 0.56
11.45
What is the molar mass of AlCl3?
133.33g
The density of an object is known to be 2.40 g/mL. If the object has a mass of 36.0 g, what would its volume be?
15.0 mL
Solve and give answers in the correct number of significant figures: 13.50 + 5.1
18.6
Give the electron configuration for S
1s^2 2s^2 2p^6 3s^2 3p^4
Give the electron configuration for Fe, and draw its arrow orbital filling diagram
1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^6
How many sigfigs are in 2400
2
The procedures of a lab call for the use of 1.95 mol of H2O. How many atoms of hydrogen would be required for this lab procedure?
2.35^24 atoms H
Methane gas is produced from rotting garbage. Methane is represented by the molecule CH4. What is the mass of a sample of methane that contains 9.04 x 1024 molecules of methane?
241 g
Silicon is known to have three isotopes: 28Si (27.98 amu) with an abundance of 92.21%, 29Si (28.98 amu) with an abundance of 4.70%, and 30Si (29.97 amu) with an abundance of 3.09%. What is the average atomic mass of Silicon?
28.09 amu
3500 / 12.66
280
How many sigfigs are in 0.00560
3
How many sigfigs are in 356
3
How many orbitals are on a p sublevel? How many electrons can a d sublevel hold?
3 orbitals, 6 electrons
Write in scientific notation: 0.000003010
3.010 x 10^-6
Solve and give answers in the correct number of significant figures: 65.1 * 0.056
3.6
Chlorine has two dominant isotopes, 35Cl and 37Cl. After analysis, the breakdown for each isotope was determined to be 75.53 percent 35Cl (mass = 34.969 amu) and 24.47 percent 37Cl (mass = 36.966 amu). Calculate the average atomic mass of chlorine.
35.46 amu
An experiment calls for the use of 2.50 mol of Mg(NO3)2. How many grams of Mg(NO3)2 are required for the experiment?
371 g
How many sigfigs are in 1.005
4
Barium nitrate has the chemical formula Ba(NO3)2. What is the mass (in g) of a 1.85 mol sample of barium nitrate?
483 g Ba(NO3)2
How many orbitals are on a d sublevel? How many electrons can a p sublevel hold?
5 orbitals, 10 electrons
Write in scientific notation: 50000.0
5.00000 x 10^4
Convert 5250 cg to kg.
5.25 x 10^-2 kg
Write in scientific notation: 0.0006730
6.73 x 10^-4
How many orbitals are on an f sublevel? How many electrons can an f sublevel hold?
7 orbital, 14 electrons
What is the percent composition by mass of Al2(C4H4O6)3?
Al = 10.83 % C=28.93% H=2.43% O= 57.81%
What is the trend in atomic radius across a period? Explain
Atomic radius decreases across a period because protons are added to the nucleus increasing the force of attraction, which pulls the electrons closer to the nucleus.
What is the trend in atomic radius down a group/family? Explain.
Atomic radius increases down a group because energy levels are added increasing the distance from the nucleus reducing the force of attraction, which allows electrons to move further from the nucleus.
What is the chemical formula for Ba and P
Ba3P2
What is the geometry of OF2
Bent polar
Which element would have a larger atomic radius: fluorine (F) or bromine (Br)? Explain.
Bromine. Bromine has more energy levels than fluorine, which increases the distance from the nucleus reducing the force of attraction and allowing electrons to move further from the nucleus.
A compound is found to have an empirical formula of C4H7. If the molar mass of the compound is measured to be 165.33 g/mol, what is the compound's molecular formula?
C12H21
Give the chemical formula to Tricarbon Hexafluoride
C3F6
An experiment is performed that creates a compound that contains only carbon and hydrogen. The compound is analyzed and found to be made up of 79.84% carbon and 20.16% hydrogen. What is the empirical formula of this compound?
CH3
What is the chemical formula for Ca and F
CaF2
Name Ca(ClO4)2
Calcium Perchlorate
What experiment did Thomson conduct? What results did he get from his experiment? What was his model of the atom?
Cathode Ray Tube, the beam attracted to the positive end of a magnet and repelled from the negative side. He concluded that there was a negatively charged particle in the atom surrounded by a positive matrix (the plum pudding model).
Which element would have a larger electronegativity value: magnesium (Mg) or chlorine (Cl)? Explain.
Chlorine. Chlorine and magnesium have the same number of energy levels, but chlorine has more protons in its nucleus. Protons being added to the nucleus increase the force of attraction, which increases the ability of the atom to attract electrons.
Rank the following elements in order of atomic radius from smallest to largest: Na, Si, Cl
Cl, Si, Na Smallest radii are located top and right, largest radii are located bottom and left on periodic table
A compound is known to contain only cobalt and nitrogen. 11.85 g of the compound is measured and found to contain 9.57 g of cobalt. What is the empirical formula of the compound?
CoN
Give the chemical formula to Cesium Carbonate
Cs2CO3
Give the chemical formula to Copper (II) Phosphite
Cu3(PO3)2
Name C2Cl4
Dicarbon Tetrachloride
What is the trend in electronegativity down a group/family? Explain.
Electronegativity decreases down a group because energy levels are added increasing the distance from the nucleus reducing the force of attraction, which decreases the ability of the atom to attract electrons.
What is the trend in electronegativity across a period? Explain.
Electronegativity increases across a period because protons are added to the nucleus increasing the force of attraction, which increases the ability of the atom to attract electrons.
Which classes of matter are pure substances?
Element, compound
What are the three classifications of matter?
Element, compound, mixture (homogeneous and heterogeneous)
Give the chemical formula to Iron (III) Nitrate
Fe(NO3)3
What experiment did Rutherford conduct? What results did he get from his experiment? What was his model of the atom?
Gold Foil Experiment, most of the alpha particles went through the gold foil and some bounced directly back. He concluded that atom was mostly empty space with a positive nucleus at center
What covalent bond is most polar
H --- F
Give the chemical formula to Carbonic Acid
H2CO3
Give the chemical formula to Hydrofluoric Acid
HF
Give the chemical formula to Thiocyanic Acid
HSCN
Name HBr
Hydrobromic Acid
Rank the three IMFs from lowest strength to highest strength.
Hydrogen Bonding > Dipole-Dipole Forces > LDFs
Which element would have a larger ionization energy value: Sr or I? Explain.
Iodine. Iodine and strontium have the same number of energy levels, but iodine has more protons in its nucleus. Protons being added to the nucleus increase the force of attraction, making it harder to remove an electron from the atom.
What is the trend in ionization energy down a group/family? Explain.
Ionization energy decreases down a group because energy levels are added increasing the distance from the nucleus reducing the force of attraction, making it easier to remove an electron from the atom.
What is the trend in ionization energy across a period? Explain.
Ionization energy increases across a period because protons are added to the nucleus increasing the force of attraction, making it harder to remove an electron from the atom.
What is an isotope? How can you tell two atoms are isotopes of each other?
Isotopes are atoms of the same element that have different numbers of neutrons. You can tell them apart by the difference in their mass numbers.
What is the chemical formula for K and P
K3P
Which IMFs are present in CF4
LDFs
Which IMFs are present in O2
LDFs
Which IMFs are present in H2S
LDFs Dipole
Which IMFs are present in H2
LDFs, Dipole-dipole, H-bonds
What is the chemical formula for Li and O
Li2O
What is the geometry of CO2
Linear nonpolar
Name LiNO3
Lithium Nitrate
Name Mg3N2
Magnesium Nitride
What is molar mass?
Mass of one mole of a substance measured in grams (taken from the amu mass of the element on the periodic table)
How did Mendeleev organize the periodic table?
Mendeleev arranged the elements in order of increasing atomic mass and in families according to the properties of the elements.
What are the physical properties that define a metal?
Metals are solids at room temperature, shiny (lustrous), and are good conductors of heat and electricity
What are the base unites of the metric system? What does each measure?
Meters = length Grams = mass Liters = volume
What is the chemical formula for Mg and S
MgS
How did Moseley organize the periodic table?
Moseley kept Mendeleev's arrangement, but arranged the elements in order of increasing atomic number
Give the chemical formula to Nitrogen Disulfide
NS2
Name NiS2
Nickle (IV) Sulfide
What are the physical properties that define a nonmetal?
Nonmetals are typically gases at room temperature or brittle solids, and are poor conductors of heat and electricity
Scandium has atomic number 21 and mass number 45. How many protons, neutrons and electrons does a neautral atom of this isotope have?
P = 21 N = 24 E = 21
Name HMnO4
Pergmanganic Acid
Rank the following elements in order of electronegativity from smallest to largest: O, Se, Po
Po, Se, O Electronegativity increases from right to left and decreases from top to bottom. The most electronegative element is Fluorine, so the farther to the right and top, the higher the electronegativity (not including group 18). This trend is opposite that of atomic radii
What are the three subatomic particles (particles that make up an atom)?
Protons, neutrons, electrons
What is the difference between qualitative and quantitative measurements?
Qualitative measurements are observational, quantitative measurements are numerical.
Rank the following elements in order of ionization energy from smallest to largest: Be, Ca, Ra
Ra, Ca, Be Ionization energy increases from right to left and decreases from top to bottom. The element with the highest ionization energy is helium. This trend is opposite that of atomic radii
Give the chemical formula to Disulfur Tetroxide
S2O3
What is the chemical formula for Sr and N
Sr3N2
What is the geometry of NH4 +1
Tetrahedral nonpolar
Where are the metals located on the periodic table?
The metals are located to the left of the step-ladder line (metalloids) on the periodic table
What is the relationship between a mL and a cm3?
They are equal to each other
What is the geometry of SO3 -2
Trigonal Pyramidal polar
Name N3I7
Trinitrogen Heptaiodide
Name N3O5
Trinitrogen Pentoxide
Name S3Br4
Trisulfur Tetrabromide
is burning a log a chemical property or physical property
chemical
is corrosiveness a chemical property or physical property
chemical
is flammability a chemical property or physical property
chemical
is water an element, compound, homogeneous mixture, or heterogeneous mixture
compound
is NO2 ionic or covalent
covalent
is PCl3 ionic or covalent
covalent
is SCl4 ionic or covalent
covalent
Is Copper an element, compound, homogeneous mixture, or heterogeneous mixture
element
Is trail mix an element, compound, homogeneous mixture, or heterogeneous mixture
heterogeneous mixture
is air an element, compound, homogeneous mixture, or heterogeneous mixture
homogeneous mixture
Is MgBr2 ionic or covalent
ionic
is CoS ionic or covalent
ionic
is K3PO4 ionic or covalent
ionic
How do you calculate the average atomic mass of an element?
mass of isotope x relative abundance, add all together [(percent adundance/100 x mass isotope) + (percent adundance/100 x mass isotope) + etc...]
is color a chemical property or physical property
physical
is density a chemical property or physical property
physical
is length a chemical property or physical property
physical
is mass a chemical property or physical property
physical
is melting a piece of wax a chemical property or physical property
physical
is tearing a sheet of paper a chemical property or physical property
physical
Where are the nonmetals located on the periodic table
to the right
What are the two types of mixtures, and how can you tell them apart?
• Heterogeneous = components are easily distinguished, not uniform in composition • Homogeneous = components are not easily distinguished, uniform in composition
Compare accuracy and precision
• accuracy = how close measurements are to the accepted value • precision = how close together numbers are to each other
What is the main difference between physical and chemical properties?
• physical property = can be measured/observed without changing the identity of the substance • chemical property = describes the ability of s substance to change its identity