Exam 1 Material
What is the formula for Strontium Fluoride
SrF2
A neutralization reaction occurs when an acid reacts with a base to produce these two products.
water and a salt
Why is it dangerous for a scuba diver to take a deep breath and hold it while ascending quickly to the surface? Assuming that the temperature of the diver's body is constant, name the gas law responsible for this phenomenon and explain it in the context of this situation.
Boyle’s Law states that pressure and volume are inversely related when temperature and the amount of gas are constant. As the diver ascends, the surrounding water pressure decreases. If they hold their breath, the volume of air in their lungs increases as the pressure drops. This expansion can overinflate and damage lung tissue, a condition known as pulmonary barotrauma.
What are the 3 assumptions of ideal gases made based on Kinetic Molecular Theory?
1. gases consist of various molecules and they move in constant random motion
2. the volume of individual molecules is negligible
3. forces between gas molecules are negligible
This type of intermolecular force is present between nonpolar molecules due to temporary fluctuations in electron distribution.
London dispersion forces
Convert 650 nm to m
6.50x10-7 m
Identify the substance that is oxidized in the following redox reaction:
Zn(s) + Cu2+(aq) → Zn2+(aq) + Cu(s)
Zn (zinc)
Write the equations for the first 2 electron affinities of the Selenium (Se) atom.
1. Se + e- → Se-
2. Se- + e- → Se2-
Place the following gases in order of molecular speed at 300 K: CO, SF6, H2S, Cl2, HBr.
CO (28.01 g/mol) – Lightest, fastest speed
H₂S (34.08 g/mol)
Cl₂ (70.91 g/mol)
HBr (80.91 g/mol)
SF₆ (146.06 g/mol) – Heaviest, slowest speed
This force is particularly important in the interaction between molecules like water, and it is responsible for many of water’s unique properties, including its high boiling point and surface tension
hydrogen bonding
Analysis of a compound shows that it contains 3.75 moles of C, 7.50 moles of H, and
1.25 moles of N. What is its empirical formula?
C3H6N
An element has the electron configuration [Ne] 3s² 3p⁴. Identify the element and determine how many unpaired electrons it has.
Sulfur (S, atomic number 16) with 2 unpaired electrons
Order the following elements by atomic size from largest to smallest: K, Br, Mg, P
K > Mg > Br > P
You have a closed container at a constant temperature containing 2 gases with different masses. What an you say about their average kinetic energies? What about their speeds?
Their average kinetic energies are the same
The heavier gas will move slower than the lighter gas
Rank the following molecules in order of increasing boiling point (lowest to highest): CH₃OH, CH₃CH₂OH, C₃H₈.
C₃H₈ < CH₃OH < CH₃CH₂OH
Balance the following equation
CH₄ + O₂ → CO₂ + H₂O
CH₄ + 2 O₂ → CO₂ + 2 H₂O
The ionization energy of hydrogen is 2.18×10-18 J. What is the minimum wavelength of light (in nm) required to ionize a hydrogen atom from its ground state? (E = hv, c = λv, c = 2.99×108 m/s)
91.2 nm
What is the electron domain and molecular geometry of the following molecule, XeF4
EDG: Octahedral
MG: Square Planar
A 15.0 L container holds a mixture of three gases at 350 K. The mole fractions of gases A, B, and C in the mixture are 0.4, 0.3, and 0.3, respectively. The total pressure in the container is 3.2 atm. Calculate the partial pressures of gases A, B, and C. (Pg = XgPtotal)
Partial Pressure of Gas A = 1.28 atm
Partial Pressure of Gas B = 0.96 atm
Partial Pressure of Gas C = 0.96 atm
Rank the following substances in order of increasing strength of intermolecular forces (from weakest to strongest): CH4, H2O, C2H5OH, I2
CH4 < I2 < C2H5OH < H2O
Magnesium forms Mg2+, and phosphate is PO43-. What is the correct formula for magnesium phosphate?
Mg₃(PO₄)₂
Use standard enthalpies of formation to calculate ΔH for the following reaction:
C3H8(g)+5O2(g)→3CO2(g)+4H2O(g) ΔH = ?
Given the standard enthalpies of formation (ΔHf° in kJ/mol):
C₃H₈ (g) = -104
CO₂ (g) = -393
H₂O (g) = -242
−2043 kJ
Draw all 4 resonance structures for the polyatomic ion PO43- , include formal charges.
4 Structures: P with a double bond to one O and a single bond to the rest, rotates among all 4 O's
If the molar mass of helium is 4 g/mol and the temperature is 300 K, calculate the approximate root mean square speed of a helium atom. (Use R = 8.314 J/mol·K)
1367 m/s
Draw a diagram showing the ion-dipole interaction between the ions of LiCl salt and water.
Include:
- the partial charges present in water
- a dotted lines representing the electrostatic forces between the ion and water
(Draw on Board)