CHEMISTRY COMMUNITY

Sarah Wax 1G

Remember to always balance OH with H2O, otherwise the equation won't balance in the long run.

Sarah Wax 1G

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

Sarah Wax 1G

Basically, just know the properties of a catalyst, why they're used, how activation energy is affected, and calculations revolving around activation energies.

Sarah Wax 1G

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.

Sarah Wax 1G

I agree with the commentator above. Ketones have their oxygens somewhere within the chains while aldehydes only END their chains with O.

Sarah Wax 1G

What did one titration tell the other?
Let's meet at the endpoint.

Sarah Wax 1G

Stop making electrochem jokes.
They're too charged.

Sarah Wax 1G

How many fish are salty?

TuNA

Sarah Wax 1G

I believe that Uraniam Argon Copper Tellurium.

U Ar CuTe.

Sarah Wax 1G

There should be someone who regulates these chem jokes.

They're far too basic for my taste.

Sarah Wax 1G

Why did the sodium cross the road?

Because it could not wait N-A longer.

Sarah Wax 1G

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.

Sarah Wax 1G

Q: What do you call a clown who's in jail?
A: A silicon.

Sarah Wax 1G

Q: What did one ion say to the other?
A: I've got my ion you.

Sarah Wax 1G

It's so exciting when multiple electrons gather in the bar.
Why?
Because it's so charged with energy.

Sarah Wax 1G

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.

Sarah Wax 1G

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.

Sarah Wax 1G

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.

Sarah Wax 1G

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.

Sarah Wax 1G

I would agree with the above statement. If anything, assume that whatever details Lavelle leaves out of the question are going to be constant.

Sarah Wax 1G

Girl, do you like salt?

Why?

Because you're so-dium fine.

Sarah Wax 1G

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.

Sarah Wax 1G

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...

Sarah Wax 1G

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...

Sarah Wax 1G

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...

Sarah Wax 1G

Also, anything involving bond enthalpies, enthalpies of formation, and calculating energy from a calorimeter will be on the test.

Sarah Wax 1G

What did the chemist say to his crush?
You're hotter than a Bunsen burner turned up all the way.

Sarah Wax 1G

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...

Sarah Wax 1G

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...

CHEMISTRY COMMUNITY

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Homework Problem 8.9