CH. 1-2
Is combustion a physical or chemical change?
Chemical change.
How many molecules are in a mole?
6.022 x 10^23 molecules per mole (Avogadro's Number)
If I have a 12 L container at a pressure of 7 atm and a temperature of 298 K, how many moles of gas are there?
About 3.4 moles
Find the frequency of a wavelength of 600 nm.
Frequency = 5 x 10^14 Hz
What is the electron geometry and molecular geometry of XeF2?
Electron Geometry: Trigonal Bipyramidal
Molecular Geometry: Linear
What kind of property are boiling point, melting point, and density?
Physical property.
How many moles of Oxygen gas are in 64 grams of Oxygen?
4 moles of Oxygen gas
If I have a 3 L balloon at 298 K, what will the new volume be at 598 K (pressure is constant)?
About 6 Liters
Find the energy when the light's wavelength is 480 nm.
E = 4.14 x 10^-19 Joules
What atom is the bond dipole pointing towards in NaF?
The bond dipole points towards F because it is more electronegative and has a partial negative charge, while Na is less electronegative and has a partial positive charge.
How many Significant Figures are in following numbers?
0.80 , 10.0 , 0.000009 , 1000
2 S.F. , 3 S.F. , 1 S.F. , 1 S.F. or 4 S.F. (ambiguous)
Balance the equation:
SiCl4 + H2O --> H4SiO4 + HCl
SiCl4 + 4 H2O --> H4SiO4 + 4 HCl
If the enthalpy of combustion of one mole of methane releases 891 kJ/mol (enthalpy is -891 kJ/mol), how many kJ of energy are released by burning 3 moles of methane?
Enthalpy of reaction= -2673 kJ
Energy released = 2673 kJ
Define Ionization Energy and describe the Periodic Table trend (in which directions on periodic table does IE increase or decrease)?
IE is the energy needed to remove an electron from an atom.
IE increases moving from left to right
IE decreases moving from top to bottom
Which of the following are polar molecules?
CH4 , H2O, NH3
Non-polar , Polar , Polar
What is the formula of a compound that is about 53% Aluminum (by mass) and about 47% Oxygen (by mass)?
Al2O3
What is the percent yield if I get 0.1 moles of Oxygen gas from a reaction that has a theoretical yield of 10 grams of Oxygen gas?
Percent Yield = 32%
A 500 gram sample of water is heated from 10 Celsius to 90 Celsius, calculate the amount of heat absorbed (in kJ) by the water. (We are looking for q, and C is equal to 4.184 Joules/gram*Celsius)
q= mC(delta)T
q = 167.4 kJ
Draw the lewis structure of Krypton.
Temperature (higher temp = greater kinetic energy)
Surface area (number of moleucles in position to enter gas phase)
Intermolecular forces (greater force requires greater kinetic energy needed for molecules to escape surface)
What is the name of these compounds?
CO , HI , NH4+
Carbon monoxide, Hydroiodic acid, Ammonium (it's an ion)
How many mL of 2.50 M NaOH solution are required to make 525 mL of a 0.150 M NaOH solution?
Answer: 0.0315 L or 31.5 mL
Exothermic process - energy flows out of system to surroundings (q < 0)
Endothermic process - energy flows into system from surroundings (q > 0)
Describe the relationship of bond length and bond energy.
Bond length is greater as bond energy is weaker, and vice versa (bond length is shorter as bond energy is greater)
What is the hybridization of a carbon in a nitrile group (C≡N)?
sp1 , sp2 , or sp3
Answer is sp1 because it has a single triple bond and a single single bond.