Kc vs Kp


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connie 2C
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Kc vs Kp

Postby connie 2C » Mon Jan 20, 2020 8:35 pm

when a chemical equation is written and all the reactants and products are gases, do you use Kp rather than Kc? in what cases do you use Kc rather than Kp?

ayushibanerjee06
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Re: Kc vs Kp

Postby ayushibanerjee06 » Mon Jan 20, 2020 8:42 pm

You use Kp when all the products and reactants are gases and the question includes units like bar/atm/pa. You use Kc when the products and reactants are given in moles or molarity, even if the products and reactants are gases. If the question asks for Kp and the question only gives you information about moles/molarity, use the ideal gas law and solve for pressure (P= (n/v)RT). Vice versa if they ask for Kc and they only give you information about pressure. Also, keep in mind there are different gas constants, so use the one that fits the units you have. Hope this helps.

Rida Ismail 2E
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Re: Kc vs Kp

Postby Rida Ismail 2E » Mon Jan 20, 2020 8:48 pm

Kc is used when you have the molarity of a solution. Kp is always used with gases.

Justin Quan 4I
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Re: Kc vs Kp

Postby Justin Quan 4I » Tue Jan 21, 2020 10:13 am

To add on, you use Kp when the reactants and products are gases. If your reaction has gases and/or aqueous substances, then use Kc. However, if you're still having trouble deciding, you should check the units to ensure you're using the right K, for example Barr (pressure) vs M (concentration).

Minh Ngo 4G
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Re: Kc vs Kp

Postby Minh Ngo 4G » Tue Jan 21, 2020 10:16 am

If all the reactants are gas then use Kp. You can calculate Kc for gas too but they would have to explicitly tell you so

Ying Yan 1F
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Re: Kc vs Kp

Postby Ying Yan 1F » Thu Jan 23, 2020 12:37 pm

It really depends what information the problems gives you. If the concentrations of the reactants and products are given, then you you Kc, on the other hand, if the pressure of the reactants and products are given then you use Kp.

ValerieChavarin 4F
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Re: Kc vs Kp

Postby ValerieChavarin 4F » Thu Jan 23, 2020 2:18 pm

It depends on what asked and given. If you are calculating molar concentration then you would use Kc.

805373590
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Re: Kc vs Kp

Postby 805373590 » Thu Jan 23, 2020 2:52 pm

You can use kp when the reactants and products are gases and the partial pressures of the gases are given rather than their concentrations

vanessas0123
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Re: Kc vs Kp

Postby vanessas0123 » Thu Jan 23, 2020 3:35 pm

You calculate Kc if given concentration. Kp if partial pressures are given.

Diana Andrade_4F
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Re: Kc vs Kp

Postby Diana Andrade_4F » Thu Jan 23, 2020 4:34 pm

You use Kc when you are given a concentration, while Kp is used when given partial pressures. However, you can use Kp to find Kc if needed.

Angela Prince 1J
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Re: Kc vs Kp

Postby Angela Prince 1J » Thu Jan 23, 2020 6:30 pm

connie 2C wrote:when a chemical equation is written and all the reactants and products are gases, do you use Kp rather than Kc? in what cases do you use Kc rather than Kp?

You can use whatever is convenient when they're all gases. You cannot use KP if it's not a gas.

Zoe Gleason 4F
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Re: Kc vs Kp

Postby Zoe Gleason 4F » Thu Jan 23, 2020 7:01 pm

Kp can be used when all the concentrations are in pressure, and Kc when they are concentrations. Pressure can be converted to concentration by using PV=nRT (and vice versa), but all the species must be in the gas phase to use Kp.

Leila_4G
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Re: Kc vs Kp

Postby Leila_4G » Thu Jan 23, 2020 7:16 pm

From what I understand, pressures can be used with Kc or Kp but concentrations can only be used with Kc. Right?

Gurmukhi Bevli 4G
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Re: Kc vs Kp

Postby Gurmukhi Bevli 4G » Thu Jan 23, 2020 7:57 pm

Kc is used when you're dealing with molar concentrations, or when all the substances in your reaction are aqueous. Kp is used for partial pressures, or when the substances in your reaction are all gases.

annikaying
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Re: Kc vs Kp

Postby annikaying » Fri Jan 24, 2020 12:04 pm

kp is used when dealing with gases and is usually given with units like atm or bar. kc is for molar concentrations and will be given as aqueous solutions.

905373636
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Re: Kc vs Kp

Postby 905373636 » Fri Jan 24, 2020 12:23 pm

The difference here just has to do with units used, though Kp will include all gases yes.

WYacob_2C
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Re: Kc vs Kp

Postby WYacob_2C » Fri Jan 24, 2020 8:23 pm

Kp is used when dealing with partial pressures, so typically gases. Kc is used when dealing with concentration, so aqueous species.

Emil Velasco 1H
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Re: Kc vs Kp

Postby Emil Velasco 1H » Fri Jan 24, 2020 9:32 pm

You use Kp unless it specifically asks for Kc

William Francis 2E
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Re: Kc vs Kp

Postby William Francis 2E » Fri Jan 24, 2020 10:09 pm

Kp should be used with gases since you're dealing with partial pressures rather than concentrations.

Tahlia Mullins
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Re: Kc vs Kp

Postby Tahlia Mullins » Fri Jan 24, 2020 10:15 pm

It all depends on the information given. You would use Kp when the partial pressures are given, but you use Kc when the concentration or moles or grams are given even when the reactants and products are gases.

Kylie Lim 4G
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Re: Kc vs Kp

Postby Kylie Lim 4G » Fri Jan 24, 2020 11:55 pm

For a reaction that is entirely gasses, Kp can be used if the pressure is given. Kc can be used for gasses as well if the pressure is converted to concentration, or concentration is given initially.

Megan Cao 1I
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Re: Kc vs Kp

Postby Megan Cao 1I » Sat Jan 25, 2020 12:20 am

kp is used for gases since they deal with Pressure. kc is used for questions involving molarity, generally solutions, however you can find the concentration of gases too. you would have to use the ideal gas law, pv=nrt

Caroline Zepecki
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Re: Kc vs Kp

Postby Caroline Zepecki » Sun Jan 26, 2020 9:53 pm

Kp is for partial pressures of gasses, Kc on the other hand is the equilibrium constants

Hannah Pham
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Re: Kc vs Kp

Postby Hannah Pham » Sun Jan 26, 2020 10:11 pm

If the reaction consists of all gases then you would use Kp. Kc can be used for gases as well if the gases are given in concentration rather than pressure.

105311039
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Re: Kc vs Kp

Postby 105311039 » Sun Jan 26, 2020 10:16 pm

Kp is used with partial pressures like gases such as ATM. But Kc is used when you have things like aq concentrations.

Anushka Chauhan2B
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Re: Kc vs Kp

Postby Anushka Chauhan2B » Sun Jan 26, 2020 10:25 pm

Kp should be used for gases since you are dealing with partial pressures

Jesse Anderson-Ramirez 3I
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Re: Kc vs Kp

Postby Jesse Anderson-Ramirez 3I » Sun Jan 26, 2020 11:23 pm

Kp is for gases and uses partial pressure. Kc uses concentrations.

Astrid Lunde 1I
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Re: Kc vs Kp

Postby Astrid Lunde 1I » Tue Jan 28, 2020 4:09 pm

Kp is when you deal with partial pressure so it is used for gasses. Use Kc when you see aq.

KaleenaJezycki_1I
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Re: Kc vs Kp

Postby KaleenaJezycki_1I » Tue Jan 28, 2020 6:41 pm

connie 2C wrote:when a chemical equation is written and all the reactants and products are gases, do you use Kp rather than Kc? in what cases do you use Kc rather than Kp?


Kc should be used normally, but the question will clarify if it wants molar concentrations or partial pressures. Therefore pay attention to the question, also Kc will be in units of mol.L-1 and Kp will be in bar or atm.

205405339
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Re: Kc vs Kp

Postby 205405339 » Tue Jan 28, 2020 7:12 pm

You use Kp because K=kp for all cases. Kc=K when certain conditions are met

MTanikella_1K
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Re: Kc vs Kp

Postby MTanikella_1K » Sun Feb 02, 2020 6:26 pm

Kp is used when all products and reactants in the equation are gases. Another indication to use Kp is if the question uses units like bar or atm. Kc is used when the molarity of the products and reactants is given, even though the products and reactants involved in the reaction are gases.

Aarushi Solanki 4F
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Re: Kc vs Kp

Postby Aarushi Solanki 4F » Sun Feb 02, 2020 6:31 pm

Kp is used when the quantity of gases are given in context of pressure. Kc is used when the molarity of solutions or gases are given.

Rosa Munoz 2E
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Re: Kc vs Kp

Postby Rosa Munoz 2E » Mon Feb 10, 2020 8:53 am

Kc is concentration Kp is partial pressure.

Hannah Romeo 1J
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Re: Kc vs Kp

Postby Hannah Romeo 1J » Mon Feb 10, 2020 9:29 am

You use Kc when you have concentrations in molarity snd use Kp when you have partial pressures.

Maika Ngoie 1B
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Re: Kc vs Kp

Postby Maika Ngoie 1B » Mon Mar 09, 2020 10:59 pm

In that instance, you would use Kp, Kc is used for molar concentration.

William Chan 1D
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Re: Kc vs Kp

Postby William Chan 1D » Wed Mar 11, 2020 10:12 pm

If the reactants and products are given in units of pressure (bars, atmospheres, etc.), then use kp. If reactants and products are given in units of concentration (mol/L), then use kc.

Jasmine W 1K
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Re: Kc vs Kp

Postby Jasmine W 1K » Thu Mar 12, 2020 6:50 pm

Kp is used with gases and Kc is used when you are dealing with concentrations.

Ryan Yoon 1L
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Re: Kc vs Kp

Postby Ryan Yoon 1L » Thu Mar 12, 2020 9:59 pm

Kc deals with concentrations and Kp deals with atm and torr.

Alan Cornejo 1a
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Re: Kc vs Kp

Postby Alan Cornejo 1a » Sun Mar 15, 2020 7:34 am

Kp is used in the event that you products and reactants all exists in a gas phase. Therefore we use the partial pressures of the gases and make sure the units we use as a result also take that into inclusion. For Kc we use that when we are trying to determine concentration rather than the pressure.

Bryce Barbee
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Re: Kc vs Kp

Postby Bryce Barbee » Sun Mar 15, 2020 7:37 am

It depends on if the give you pressures or concentrations. I am pretty sure that you can use both if its a gas though.

Catherine Daye 1L
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Re: Kc vs Kp

Postby Catherine Daye 1L » Sun Mar 15, 2020 7:41 am

You use Kp for gases if you use partial pressure for gases. You can also change pressure to concentration using PV=nRT and in that case, you would use Kc since you’re now using concentrations.

Gerald Bernal1I
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Re: Kc vs Kp

Postby Gerald Bernal1I » Sun Mar 15, 2020 7:42 am

Kc is used if you are given concentrations and Kp is used when you are given partial pressures.

805422680
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Re: Kc vs Kp

Postby 805422680 » Sun Mar 15, 2020 7:45 am

Kc is used when you are given concentrations, and Kp is used when you are given partial pressures of gases. When Kp is given, the products and reactants are both gases. When Kc is given, the products and reactants can consist of gases or aqueous solutions

briannam_1F
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Re: Kc vs Kp

Postby briannam_1F » Tue Mar 17, 2020 10:57 pm

Kc is used when molarity is given. When it comes to gas you only use Kp when given partial pressures or asked to convert to partial pressures.


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