Search found 29 matches
- Sun Mar 18, 2018 11:45 pm
- Forum: Balancing Redox Reactions
- Topic: Adding OH
- Replies: 6
- Views: 1000
Re: Adding OH
Remember to always balance OH with H2O, otherwise the equation won't balance in the long run.
- Sun Mar 18, 2018 11:43 pm
- Forum: General Rate Laws
- Topic: Rate constant units
- Replies: 6
- Views: 1258
Re: Rate constant units
Another thing I do is whatever the order is, the liters and moles will have an exponent one less than the order.
For fourth order, the rate constant = L^3/ mol^3 * S
For third order, the rate constant = L^2/ mol^2 * s
For second order, the rate constant = L / mol * s
For fourth order, the rate constant = L^3/ mol^3 * S
For third order, the rate constant = L^2/ mol^2 * s
For second order, the rate constant = L / mol * s
- Sat Mar 17, 2018 10:44 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: how much of catalyst do we need to know? [ENDORSED]
- Replies: 4
- Views: 713
Re: how much of catalyst do we need to know? [ENDORSED]
Basically, just know the properties of a catalyst, why they're used, how activation energy is affected, and calculations revolving around activation energies.
- Sat Mar 17, 2018 10:43 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Iced tea and water problem
- Replies: 2
- Views: 1255
Re: Iced tea and water problem
I also was conflicted on this question. I'm assuming since the ice cube starts as a solid when the reaction first goes, you need to use H of ice, and then once it's heated, use H of water.
- Sat Mar 17, 2018 10:40 pm
- Forum: *Ketones
- Topic: Keytone and Aldeyhdes
- Replies: 3
- Views: 3353
Re: Keytone and Aldeyhdes
I agree with the commentator above. Ketones have their oxygens somewhere within the chains while aldehydes only END their chains with O.
- Mon Mar 05, 2018 12:01 am
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3642910
Re: Post All Chemistry Jokes Here
What did one titration tell the other?
Let's meet at the endpoint.
Let's meet at the endpoint.
- Sun Mar 04, 2018 11:59 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3642910
Re: Post All Chemistry Jokes Here
Stop making electrochem jokes.
They're too charged.
They're too charged.
- Sun Mar 04, 2018 11:58 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3642910
Re: Post All Chemistry Jokes Here
How many fish are salty?
TuNA
TuNA
- Sun Mar 04, 2018 11:58 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3642910
Re: Post All Chemistry Jokes Here
I believe that Uraniam Argon Copper Tellurium.
U Ar CuTe.
U Ar CuTe.
- Sun Mar 04, 2018 11:56 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3642910
Re: Post All Chemistry Jokes Here
There should be someone who regulates these chem jokes.
They're far too basic for my taste.
They're far too basic for my taste.
- Sun Mar 04, 2018 11:56 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3642910
Re: Post All Chemistry Jokes Here
Why did the sodium cross the road?
Because it could not wait N-A longer.
Because it could not wait N-A longer.
- Sun Feb 18, 2018 11:58 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3642910
Re: Post All Chemistry Jokes Here
Q: What do you do with a sick chemist?
A: If you can't helium, and you can't curium, then you might as well barium.
A: If you can't helium, and you can't curium, then you might as well barium.
- Sun Feb 18, 2018 11:58 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3642910
Re: Post All Chemistry Jokes Here
Q: What do you call a clown who's in jail?
A: A silicon.
A: A silicon.
- Sun Feb 18, 2018 11:57 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3642910
Re: Post All Chemistry Jokes Here
Q: What did one ion say to the other?
A: I've got my ion you.
A: I've got my ion you.
- Sun Feb 11, 2018 10:42 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3642910
Re: Post All Chemistry Jokes Here
It's so exciting when multiple electrons gather in the bar.
Why?
Because it's so charged with energy.
Why?
Because it's so charged with energy.
- Sun Feb 11, 2018 10:41 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Salt Bridge
- Replies: 7
- Views: 874
Re: Salt Bridge
Like in lecture, a salt bridge keeps overall potential neutral, without which, electrons would build up at the cathode. A salt bridge must be used in order for the Galvanic cell to work.
- Sun Feb 11, 2018 10:38 pm
- Forum: Balancing Redox Reactions
- Topic: Oxidation
- Replies: 5
- Views: 871
Re: Oxidation
I agree with the above responder. Basically, an oxidation number is the charge of an element within a certain compound. For example, in H2O, Hydrogen's oxidation number is +1 and Oxygen's is -2.
- Sun Feb 04, 2018 10:58 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Quiz 1, #1
- Replies: 2
- Views: 435
Re: Quiz 1, #1
Exactly. There's a difference because one of the methods (bond enthalpies) relies on only the average bond energies/enthalpies for a certain bond. However the other method (enthalpies of formation) are specific to that molecule and tell you the exact energy which is needed to form it.
- Sun Feb 04, 2018 10:56 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: Test question [ENDORSED]
- Replies: 16
- Views: 1788
Re: Test question [ENDORSED]
Yeah, I basically just put "energy can be neither created nor destroyed, only conserved." My TA told me that as long as you understood the concept, they didn't dock you for not being 100% accurate.
- Sun Feb 04, 2018 10:54 pm
- Forum: Van't Hoff Equation
- Topic: Entropy and enthalpy
- Replies: 2
- Views: 482
Re: Entropy and enthalpy
I would agree with the above statement. If anything, assume that whatever details Lavelle leaves out of the question are going to be constant.
- Sun Jan 28, 2018 3:15 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3642910
Re: Post All Chemistry Jokes Here
Girl, do you like salt?
Why?
Because you're so-dium fine.
Why?
Because you're so-dium fine.
- Sun Jan 28, 2018 3:12 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Enthalpy calculated from Bonds vs Enthalpy of formation
- Replies: 3
- Views: 471
Re: Enthalpy calculated from Bonds vs Enthalpy of formation
Exactly. Using enthalpies of formation are a lot more accurate because it's the exact energy needed to form one mole of a substance. Bond enthalpies merely use averages of the exact energy needed to break/form a bond.
- Sun Jan 28, 2018 3:07 pm
- Forum: Phase Changes & Related Calculations
- Topic: When to use Kelvin or Celsius
- Replies: 10
- Views: 6876
Re: When to use Kelvin or Celsius
Everyone posting in this forum is correct. Usually, when using deltaT, it doesn't matter whether you use K or C because a change in temperature for either will result in the same numbers. However, when using just T in an equation, you need to use the other labels in order to determine whether or not...
- Sun Jan 21, 2018 7:01 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: q(sys) = -q(surr)
- Replies: 3
- Views: 2586
Re: q(sys) = -q(surr)
Usually, we just use -q(sys) = q(surr). That way everything remains simple. If we solve for the heat of system and we get q= -10 kJ, we know that the q of the surroundings is +10 kJ, and therefore the reaction of the system is exothermic. If the opposite signs occur, the reaction of the system is en...
- Sat Jan 20, 2018 4:01 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Most Accurate Method [ENDORSED]
- Replies: 3
- Views: 384
Re: Most Accurate Method [ENDORSED]
Yeah, and remember that when using enthalpies of formation to check that the state of the molecule that you're using corresponds to the equation that you're trying to find the enthalpy for. Also: enthalpies of formation are the only enthalpies where you use (sum of products' enthalpies) - (sum of re...
- Sat Jan 20, 2018 3:58 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Week 3 Test Topic is endorsed
- Replies: 37
- Views: 4903
Re: Week 3 Test Topic is endorsed
Also, anything involving bond enthalpies, enthalpies of formation, and calculating energy from a calorimeter will be on the test.
- Sun Jan 14, 2018 6:39 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3642910
Re: Post All Chemistry Jokes Here
What did the chemist say to his crush?
You're hotter than a Bunsen burner turned up all the way.
You're hotter than a Bunsen burner turned up all the way.
- Sun Jan 14, 2018 5:42 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Hess's Law: Method 1
- Replies: 3
- Views: 404
Re: Hess's Law: Method 1
Adding up enthalpy changes using Method 1 is a smart way to go about finding the overall delta H. Essentially, if you don't have the net equation that you need in order to solve for H, then you can switch around and multiply equations in order to get your final solution. Like it's been said, equatio...
- Sun Jan 14, 2018 1:19 pm
- Forum: Calculating Work of Expansion
- Topic: Homework Problem 8.9
- Replies: 2
- Views: 439
Homework Problem 8.9
Homework problem 8.9 asks us to calculate the internal energy of the gas using pressure (750 torr), an expansion in volume (+1501 mL), and a gain in energy (5.50 kJ). What equation do we use to calculate the internal energy of the gas given the fact that the system both gains energy in heat and does...