Gas Laws
What conditions does "STP" indicate?
0 C and 1 atm
Classify the following reaction (multiple reaction types may apply):
Pb(NO3)2(aq) + 2NaCl(aq) → 2NaNO3(aq) + PbCl2(s)
Precipitation/Double replacement reaction
How many protons, neutrons, and electrons are in 170Tm3+?
69 protons, 101 neutrons, 66 electrons
On a heating curve of water, the flat line at 100°C represents this.
Water evaporating to form a gas
What are the IMF force(s) present in NH3(g)?
London dispersion forces, dipole-dipole forces, and hydrogen bonding
A way to increase the pressure of a sample gas without deliberately changing volume.
Increase gas particles or increase its temperature in a rigid container.
Molarity (M) of a 6 L solution that contains 66 g of dissolved KI
1 mole KI = 39.10 + 126.90 = 166.00 g
66g x (1 mole/166g)=0.398 mole/6L = 0.066 M
What is the condensed electron configuration for Ge2+?
[Ar] 4s2 3d10
What is the critical point of a subtance?
The temperature and pressure past which gas and liquid are indistinguishable.
Write the name and lewis structure for the ClO4- ion?
Perchlorate [see drawing]
A car tire at 3 atm and 25°C contains how many moles of air if its volume is 8.0 L?
n=PV/RT
R = 0.082 L.atm/mol.K
n=(3atm ×8.0L)/(0.0821L.atm/mol.K × 298K)
Balance the chemical equation:
Cu + HNO3 → Cu(NO3)2 + NO2 + H2O
Cu + 4 HNO3 → Cu(NO3)2 + 2 NO2 + 2 H2O
Identify the most electronegative element where the highest energy valence electron could have the following quantum numbers: n = 6 l = 1 ml = 0 ms = 1/2?
Iodine
Given the following reactions and their respective ΔH values, determine the standard heat
of reaction (in kJ) for the reaction below using Hess’s Law:
B2H6 (g) + 6 Cl2 (g) → 2 BCl3 (g) + 6HCl (g) ΔHrxn = ?
BCl3 (g) + 3H2O (l) → H3BO3 (g) + 3HCl (g) ΔH1 = -112.5 kJ
B2H6 (g) + 6H2O (l) → 2H3BO3 (g) + 6H2 (g) ΔH2 = -493.4 kJ
½ H2 (g) + ½ Cl2 (g) → HCl (g) ΔH3 = -92.3 kJ
-1376 kJ
What is the molecular geometry and bond angle of NO2?
bent, < 120
A cylinder with a moveable piston contains 40L of air at pressure of 1 atm at 36°C. If the temperature is kept the same but the pressure inside the cylinder changes to 8 atm, what is the new volume of the container?
Boyle's Law
K=PV = (1 atm)(40L)
K= 40
V = K/P = 40/(8atm) = 5L
How many grams of MgO can you produce if you start with 37g of O2?
2Mg(s) + O2(g) → 2MgO(s)
Molar mass O₂ = 32 g/mol
37g O2 x (1 mol O2/32g) = 1.16 mol O2
1.16 mol O2 x (2 mol MgO/1 mol O2) = 2.31 mol MgO
Molar mass MgO = 40.3 g/mol
2.31 mol MgO × 40.3 g/mol = 93.1 g MgO
The first eight successive ionization energies (IE1, IE2, …) for an element are 578; 1817; 2745; 11,577; 14,842; 18,379; 23,326; and 27,465 kJ/mol. If the principal quantum number of the 1st removed electron (IE1) is 3, what element is it?
Al
How many joules of energy does it take to heat 576mL of water from 1℃ to 30℃?
Specific Heat Capacity of Water = 4.184 J/g℃
q=576mL × 4.184 J/g℃ × 29℃ = 69,890 J
Rank the following in terms of predicted melting point: LiF, MgCl2, NaBr, BeO, CsI
CsI < NaBr< LiCl < MgF2 < BeO
A gaseous hydrocarbon is 85.6% C and 14.4% H by mass. It has a density of 4.59 g/L at 2.0 atm and 25 C. What is the molecular formula of the gas?
C4H8
If you have 40 g N2 and 9 g H2 for the reaction shown below, how many grams of NH3 will you produce?
N2(g) + 3H2(g) → 2NH3(g)
Molar mass N₂ = 28 g/mol
40g N₂ x (1 mol N₂/28g) = 1.43 mol N₂
Mole to Mole Ratio
1.43 mol N₂ x (2 mol NH3/1 mol N₂) = 2.86 mol NH3
Convert back to grams
Molar mass NH₃ = 17.0 g/mol
2.86 mol NH3 x (17 g/1 mol NH3) = 48.62g NH3 LR
Molar mass H₂ = 2 g/mol
9.0 g x (1 mol H₂/2g) = 4.50 mol H₂
Mole to Mole Ratio
4.50 mol H₂ x (2 mol NH3/3 mol H2) =3 mol NH3
More than 2.86 mol NH3 when working with N2
A new element Montgenium is found to consist of 3 isotopes, two of which are 312.4 amu (35 % abundant), and 314.6 amu (45% abundant). Given that the average atomic mass is 312.93 amu and the lightest isotope has 184 neutrons, what is the atomic number of Montgenium?
126
You place 18g of ice at 0 °C into 400g of liquid water at 25°C in an insulated container. After a while, the ice completely melts. What is the final temperature of the mixture?
Heat of Fusion of Water = 6.02 kJ/mol
Specific Heat Capacity of Water = 4.184 J/g℃
Energy of melted ice = 18 g×6.02 kJ/18.02 g = 6,010 J
Change in temp of water while ice is melting = 6010J/(400g x 4.184 J/g℃) = 3.6 ℃
Temp of water after ice melted = 25°C - 3.6 ℃ = 21.4°C
Avg. temp of water and ice = ((400g)(21.4°C) + (18g)(0°C))/(418g) = 20.48°C
What is the lewis structure of B2H6?
[see drawing]