Molarity
Calculate the molarity of AlCl3 if 0.220 mol AlCl3 is dissolved in enough water to make 0.500 L of solution.
0.440 M AlCl3
Is wood burning endothermic or exothermic?
exothermic
What does specific heat mean?
The amount of heat required to raise exactly 1 g of the substance by exactly 1 C
What is the relationship between wavelength, frequency, and speed?
Wavelength and frequency are inversely proportional, while energy and wavelength are directly proportional.
3A+B → C ΔH = 30.0 KJ
D → 7E ΔH = 83.0 KJ
2F → G+2K ΔH = -73.4 KJ
a. What is ΔH for C → 3A+b
b. What is ΔH for 3D → 21E
c. What is ΔH for 2G+4K → 4F
a. ΔH = -30.0 KJ
b. ΔH = 2.49x102 KJ
c. ΔH = 1.47x102 KJ
What is the balanced chemical formula of the salt that is produced from phosphate reacting with sodium hydroxide?
Na3PO4
Define what a state function is.
It is a property of a system that only depends on the state of the system.
Example: pressure
Substance A's specific heat value is around 6 J/g C while Substance B's specific heat value is 4.2 J/g C. What does this tell us about the substances?
Substance A can resist higher temperatures than Substance B.
Which has the higher frequency and lower energy: radio waves or gamma rays?
Gamma rays has the higher frequency.
Radio waves has the lower energy.
Please calculate ΔH for the reaction 4NH3(g)+5O2(g) → 4NO(g)+6H2O(g)
N2(g)+O2(g) → 2NO(g) ΔH = -133.3 KJ
N2(g)+3H2(g) → 2NH3(g) ΔH = -57.3 KJ
2H2(g)+O2(g) → 2H2O(g) ΔH = -555.5 KJ
ΔH = -1.82x103 KJ
How many moles of sulfuric acid are in 63.5 mL of a 3 M solution?
0.190 mol sulfuric acid
When a person pushes a car, is the system (car) or the surroundings (person) doing the work?
The surroundings (person) is doing the work.
Calculate the final temperature after 1485 J of energy is added to 16.7 g of water at 23.4 C.
Calculate the frequency of light that has a wavelength of 511 nm.
5.87 x 10^-14 s^-1
Using the ΔH of formations provided, please calculate the ΔH of the reaction C2H5OH(s)+3O2(g) → 2CO2(g)+3H2O(l)
ΔH of formation for C2H5OH(s): -343.4 KJ
ΔH of formation for CO2(g): -567.8 KJ
ΔH of formation for H2O(l): -157.5 KJ
ΔH = -1.265x103 KJ
How many grams of solute are in 250 mL of 0.10 M CaCl2 solution?
2.8 g
Can you create energy by stirring your coffee really fast?
No, energy is neither created or destroyed (1st Law of Thermodynamics)
Calculate the delta H of the reaction.
2C4H10 + 13 O2 --> 8 CO2 + 10H2O
C4H10: -147.3 kJ/mol
H2O: -241.8 kJ/mol
CO2: -393.5 kJ/mol
-5271 kJ
What is the wavelength in nanometers of a photon that has an energy of 4.01 x 10^-19 J?
496 nm
Please calculate ΔH for the reaction 2OF2(g)+2S(s) → SO2(g)+SF4(g)
OF2(g)+H2O(l) → O2(g)+2HF(g) ΔH = -357.7 KJ
SF4(g)+2H2O(l) → 4HF(g)+SO2(g) ΔH = -953.2 KJ
S(s)+O2(g) → SO2(g) ΔH = -432.1 KJ
ΔH = -626.4 KJ
15 g of FeCl3 is dissolved in 450 mL of solution. What is the concentration of Cl-?
0.617 mol/L or M
What does the variable U represent?
It is the internal energy of the system, which is the sum of all kinetic and potential energies.
Use the equations below to calculate delta H of:
Z + Q --> X + 2R
1: E+ 2D --> Z + Q H= 41.7 kJ
2. J + A --> E + 2D H= -17.1 kJ
3. J + A --> X + 2R H= 10.6 kJ
-14 kJ
Calculate the emission wavelength of the photon that is emitted when an electron in a hydrogen atom drops from 5th energy level to the 2nd energy level. Is this photon in the visible region?
434 nm
It is in the visible region
Please calculate ΔH for the reaction _Al(s)+_Cl2(g) → _AlCl3(s) (balance first)
2Al(s)+6HCl(aq) → 2AlCl3(aq)+3H2(g) ΔH = -1234.5
HCl(g) → HCl(aq) ΔH = -59.3 KJ
H2(g)+Cl2(g) → 2HCl(g) ΔH = -2123.8 KJ
AlCl3(s) → AlCl3(aq) ΔH = -432.3 KJ
2Al(s)+3Cl2(g) → 2AlCl3(s)
ΔH = -7.097x103 KJ