ICE tables moles vs molarity

[Kloey Reyes]

When doing ICE tables, is it correct that you can use either moles or molarity? If so, why is that?

[Rachel Chan 1B]

You can only use molarity (mol/L). This is because the equilibrium constant (K) is based on the concentrations of the reactants and products, and not on the number of moles present. If you do use moles, you will most likely get an inaccurate answer (unless the volume of the container happened to be 1 L).

[Alaura Dis 1H]

Using molarity is best since you can always use molarity. There are cases where you can use moles and afterwards you would divide by volume to get molarity, however this only applies to certain problems, so I just always stick with using molarity in ice tables.

[Joelle Tran 1K]

You use the K (equilibrium constant), which is calculated using the molar concentrations of the substances in the chemical equation, so you should use the molarities and not just the moles.

[Charlotte McDonough 2B]

Hi! You should use molarity when calculating K and/or finding equilibrium concentrations. From those values you can solve for the amount of moles of a substance present, if needed (and provided you know the volume of solution you are working with). Be sure to check your work for this, I know its quite a common mistake!

[Sanjana Narayanan 2J]

In most examples that we've covered in lectures, we use molarity in ICE tables. This also seems to be generally easier because we do not have to worry about converting between moles and molarity when calculating k values.

[205705413]

It depends on the problem. Usually you use molarity, however when calculating the pH of a solution prior to it reaching the equilibrium point (during a titration), you would use moles instead of molarity. If you take chem 14BL, the professor clarifies when to use which.

[Nancy_La_1H]

ICE tables can be in moles or molarity (depending on what the problem gives you). However, when you are trying to find the equilibrium constant, K, you would have to convert everything to molarity.

[Aaron Kim 1J]

You can use either moles or molarity, but always check and make sure that all the values are in terms of one or the other (i.e. ensure that if you use moles, all the values on the table are in terms of moles). Though, when calculating the equilibrium constant, K, you'd need to convert all values to molarity.

[rachelsjordan 1K]

I'm pretty sure you use moles to calculate molarity if the number of moles or grams of a substance is given to you with the volume. Other than that you just use molarity for the ICE tables

[Adithi Ayyala 2G]

In ICE tables we are truly just trying to observe a change in the system, so moles are also acceptable. However, to find a K value (equilibrium constant) using Molarity is the best way to yield this value.

[Claire Kim 1F]

When doing ICE tables, is it correct that you can use either moles or molarity? If so, why is that?

As long as you use only moles or only molarity throughout the entire ICE table you should be okay. The reason is that if you use moles, at the end you can translate it into molarity based on the volume and if you use molarity it's based on the same amount of volume.

[riddhiparikh]

On ICE tables, it is usually in your best interest to use molarity because that is what is most commonly asked for. It is important to make sure you check what the question is asking for though. You use molarity because K, the equilibrium constant, is based on concentrations of products and reactants, not the number of moles.

[Parinita Jithendra 2A]

When using K (equilibrium constant), it is best to use molarity just so that it makes the equations easier.

[Madison Yee 2B]

you generally use molarity. you only use moles when you're doing a problem about a titration.

[trevina_brown_2A]

Hi! You should use molarity when calculating K and/or finding equilibrium concentrations. From those values you can solve for the amount of moles of a substance present, if needed (and provided you know the volume of solution you are working with). Be sure to check your work for this, I know its quite a common mistake!

This was a good explanation.

[Palig Kechichian 3F]

For ICE tables you should probably use molar concentrations because you'd be less likely to make any calculation errors

[Edriana J Altea 2G]

It is best to use molar calculations because it is the standard and more common.

[Jacquelyn Rivera 2I]

It's best to use molarity because of the fact that K is specific to concentrations of specimens.

[Zoe Staggs 3B]

ICE tables require you to use molarity, which is the ratio of moles/L. This is because the equilibrium constant relies on concentration values of reactants and products. A lot of problems use 1 L to simplify though, which means moles=molarity.

[Tara Cumiskey 3K]

You can use moles or molarity, but I would recommend molarity.

[Shay Crookall 2L]

To avoid further conversions after calculating K, you should use molarity instead of moles. Usually, if moles are given in the problem it’s because volume is as well and you are meant to convert from mol -> mol/L

[cnyland]

Use molarity!

[Rebecca_Park_1G]

For problems concerning equilibrium, it's best to use molarity. Kc, which can be determined with an ICE table, deals directly with concentration/molarity.

[Suraj Kulkarni 2B]

For ICE tables, you definitely only want to use molarity here. For example, I know that some of the problems covered in the homeworks don't outright provide the molarity, so you would have to use the moles that are provided and divide that by the volume provided in the problem (to end up with moles/liter which are the units for molarity). Unless the volume is 1 liter, I wouldn't just assume that the molarity would be the same as the number of moles!

[Ashwin Kumar 3D]

For ICE tables, I think you should use molarity instead of moles because while molarity includes the measurement of liters of solute, moles do not factor in this calculation. This is important to consider when doing ICE table problems because you want your final answer to be in moles per liter, which is the measurement for molarity, instead of just moles! Hope that answers your question :)

[Richard Colgrove 1A]

Using molarity can also be more helpful when a system is compressed (volume decreases) because the moles don't change but the molarities do, which causes a shift toward the products/reactants depending on the exact chemical reaction.

[Valerie M Dis 2E]

For ICE tables, using molarity would be best. This is because the equilibrium constant, K, is in terms of the concentration values of the reactants and products.

[Casey Fineberg]

Hi. The equilibrium constant relies on the concentrations of reactants and products. Therefore, I would suggest that you use molarity (moles/L) just for practice as it might be necessary to know the volume as these problems get more complex. For now, they are implying that the L (liter) value is 1, so in this case, you could technically use either as they will yield the same solutions (as long as that unit stays consistent throughout).

[Viviana Hsiao 1G]

you would use molarity instead of moles, since we are dealing with the equilibrium constant K. The moles and volume will usually be given in the problem, so you can calculate the molarity.

[Andrew Dinh 2L]

It's more conventional to use molarity, but like another post since conventional K values are also calculated using molarity. If you were trying to find the value of an unknown "x" for the Change line, your answer might be off if you use moles instead, so it's safer to use molarity.

[Zain Syed 1E]

Pretty sure mostly molarity because it takes into account the whole reaction where it also includes the moles along with the volume. If the volume wasn't considered, then the ice table wouldn't represent the situation correctly. Molarity=n/V, so it takes into account all the aspects of the reaction.

[Alicia Li 2E]

I agree with what was previously said; I also think because the equilibrium deals with gases, pressure and volume (as well as temperature) plays a role in the equilibrium. Thus, it would be more accurate to use molarity than just moles.