Naming
Co(NO3)2
m = mol solute/kg solvent
.175m = x mol KF/0.347kg H2O = .0607mol KF (58.0967g KF/1mol KF) = 3.53g KF
Calculate the mass of 500mL of ethanol (in kg) if you know the density of ethanol to be 0.798g/cm3
m = (.798g/cm^3)(500) = 399g = 0.399kg
What does it mean when an atom is reduced? When it's oxidized?
it gained e-, it lost e-.
Draw the Lewis Structure for sodium oxide
[Na]+ [O]2- [Na]+
(oxygen has full valence shell)
What's the name of this compound?
Sr(C2H3O2)2
strontium acetate
If it requires 54mL of .10M NaOH to neutralize 125mL of HCl solution, what is the concentration of the HCl solution?
NaOH + HCl -> H2O + NaCl
54mL = .054L, 125mL HCl = .125 L HCl
.10mol NaOH/1L NaOH (.054L NaOH) = .0054mol NaOH
.0054mol NaOH (1mol HCl/1mol NaOH) (1/0.125L HCl) = .0432M HCl
Surprise! I hate math and didn't want to write another question-- you have plenty already :/
Tell me one weird thing about myself for 200 points. Has to actually be weird not "you have 2 cats." If answer is debatable everyone vote whether or not they think it's weird enough to qualify
Answers may vary.
Which family is most metallic in character? Why?
options: alkali metals, alkali earth metals, transition metals, halogens, noble gases
It's the alkali metals! They are the furthest to the left (periodic trends) and are the MOST REACTIVE. Want to lose electrons the most!
What are the n, l and ml values for the 5d orbital?
n = 5, l =2, ml=-2,-1,0,1,2
How? n = 5 because it tells us the level is 5
l=2 because d orbitals have an l value of 2 (s=0, p=1, d=2, f=3..)
ml values = +/- l
What's the name of this compound?
Mg3N2
magnesium nitride
If the human eye has an osmotic pressure of 8.00 atm at 25oC, what concentration of NaCl will provide an isotonic eye drop solution (note: solutions that are isotonic have equal osmotic pressure)
Pi = MRT
*25 degrees C = 298.15K
8 = M(.0206)(298.15K)
Which of the following solutions has the highest electrical conductivity?
A) 0.10M Al(NO3)3, B) 0.01M LiBr, C) 0.10M (NH4)2CO3, D) they should all be equally conductive
*(Groups should vote on whether they want a hint on what highest electrical conductivity means/how to find. If vote yes ellie check ans key)
Highest electric conductivity would have the MOST IONS!
Correct ans is A) 0.10M Al(NO3)3, Aluminum nitrate breaks into 4 ions (1 al3+ and 3 nitrate ions). That means that A = 0.40M ions, B= 0.20M ions and C = 0.30M ions.
Explain electron affinity and ionization energy. Explain the periodic trend of each one on one of the large whiteboards.
Electron affinity is how badly an atom "wants" to gain an e-. increases as you move to the right. Ionization is how much energy is required to remove a valence e- from an atom. This also increases to the right
Write the nuclear reaction for the positron emission of O-15.
Bonus 400 points if you can name what type of radiation rays are emitted during this process.
158 O -> 0+1 e + 157 N bonus points if you knew that GAMMA rays are released during this process.
Positrons are the antiparticles of an electron! Same mass, but opposite charge. During this process a proton is converted into a NEUTRON! That's why O -> N
What's the formula for sulfurous acid?
H2SO3
A sample of ore contains 5.95g of silver per ton of ore. What is the concentration of silver in this ore in ppm?
ppm = mass solute/mass solution x factor of 10^6
1 ton (2000lbs/1ton) (453.59g/1lbs) = 90,718g
ppm = 5.95g silver/90,718g x 10^6 = 6.56 ppm
Calculate the De Broglie wavelength of an e- (m=9.11 x 10-28g) traveling at a speed of 2.149 x 1010m/hr. Give your answer in meters with the correct # of significant figures.
lambda = h/mv
*(need to convert mass into kg and velocity into m/s)
m=9.11 x 10-28g = 9.11x10-31kg
2.149 x 1010m/hr (1hr/60min) (1min/60sec) = 5,969,444.44 m/s
= 6.626x10^-34 / (9.11x10^-31)(5,969,444.44) = 4341.7716
(with correct SF) = 4.34x10^3 m
Explain the law of definite proportions
All samples of a given compound have the same ratio of atoms and the same ratio of their masses!
Tetracene (C18H12) is an orange solid powder, and is combusted accidentally in Ellie's organic chemistry lab (oops) in the presence of oxygen gas.
What is the balanced chemical equation for the combustion of tetracene? Include states of matter in your equation.
C18H12(s) + 21 O2(g) -> 18CO2(g) + 6H2O(g)
Name this compound HNCO
Cyanic acid
(NCO is the cyanATE ion. plus H makes it an acid. -ate -> -ic acid)
Percent mass = mass solute/mass solution
(Rearranged/Reworded) Mass NaCl = Mass solution x Percent NaCl as a decimal
= 94.88 g (.15)
= 14.23g NaCl
Some rando in your lab somehow accidentally swallowed a drop of liquid oxygen, O2(l), which has a density of 1.149g/mL. Assuming the drop has a volume of 0.050mL, what volume of gas will be produced in the rando's stomach at body temperature (37oC) and a pressure of 1.0atm?
n= .00005mL (1mol O2/1.149mL) = .0018 mol O2
T= 37degrees C -> 310.15K
V = .0018mol(.08206)(310.15K)
= .046L O2 = 46mL O2(g)
products are SrBr2 and NH4OH which evolves into 2NH3 and 2H2O. (NH3 is a gas!) So, this is a GAS EVOLUTION RXN!
On the whiteboards or a sheet of paper if there are no whiteboards near your group, write the balanced molecular AND complete ionic equations for the reaction between cesium hydroxide and nitric acid (assume both are aqueous) and use your work to identify the spectator ions in the reaction.
M: CsOH(aq) + HNO3(aq) -> H2O(l) + CsNO3 (aq)
CIE:
Cs+(aq) + OH-(aq) + H+(aq) + NO3-(aq) -> H2O(l) + Cs+(aq) + NO3- (aq)
spectator ions were Cs+ and NO3-