Definition of reaction quotient Q, and how it is used to predict the direction of reaction
Log in Brian Walsh 9 years agoPosted 9 years ago. Direct link to Brian Walsh's post “I'm confused with the dif...” I'm confused with the difference between K and Q. I'm sorry if this is a stupid question but I just can't see the difference. How can you have a K value of 1 and then get a Q value of anything else than 1? • (30 votes) rbrtweigel 9 years agoPosted 9 years ago. Direct link to rbrtweigel's post “K is the equilibrium cons...” K is the equilibrium constant. Therefore K is revealing the amount of products to reactants that there should be when the reaction is at equilibrium. Q is used to determine whether or not the reaction is at an equilibrium. At any given point, the reaction may or may not be at equilibrium. By calculating Q (products/reactants), you can compare it to the K value (products/reactants AT EQUILIBRIUM) to see if the reaction is at equilibrium or not. If Q=K, the reaction is at equilibrium. (75 votes) tmabaso28 9 years agoPosted 9 years ago. Direct link to tmabaso28's post “Can i get help on how to ...” Can i get help on how to do the table method when finding the equilibrium constant • (10 votes) Chris 9 years agoPosted 9 years ago. Direct link to Chris's post “http://www.chem.purdue.ed...” http://www.chem.purdue.edu/gchelp/howtosolveit/Equilibrium/ICEchart.htm Try this website if you need help with ICE tables and calculating the equilibrium constant K. I don't think Khan Academy has any videos on ICE tables but I am not sure; if they do not, then I will try to get some ICE table videos in. It is a fundamental topic of chemistry and, in my opinion, just as important as stoichiometry. Emily Outen 9 years agoPosted 9 years ago. Direct link to Emily Outen's post “when setting up an ICE ch...” when setting up an ICE chart where and how do you decide which will be -x and which will be x? • (6 votes) Zenu Destroyer of Worlds (AK) 8 years agoPosted 8 years ago. Direct link to Zenu Destroyer of Worlds (AK)'s post “if the reaction will shif...” if the reaction will shift to the right, then the reactants are -x and the products are +x. (13 votes) Natalie ☣ 9 years agoPosted 9 years ago. Direct link to Natalie ☣'s post “in the example shown, I'm...” in the example shown, I'm a little confused as to how the 15M from the products was calculated. • (3 votes) yuki 9 years agoPosted 9 years ago. Direct link to yuki's post “We didn't calculate that,...” We didn't calculate that, it was just given in the problem. (7 votes) Amrit Madugundu 8 years agoPosted 8 years ago. Direct link to Amrit Madugundu's post “How can we identify produ...” How can we identify products and reactants? For example, in the reactions: 2HI <=> H2 plus I2 and H2 plus I2 <=> 2HI, the values of Q differ. In the section "Visualizing Q," the initial values of Q depend on whether initially the reaction is all products, or all reactants. Can't we just assume them to be always all reactants, as definition-wise, reactants react to give products? • (6 votes) Ernest Zinck 8 years agoPosted 8 years ago. Direct link to Ernest Zinck's post “As you say, it's a matter...” As you say, it's a matter of definition. (1 vote) Priyanka Shingrani 9 years agoPosted 9 years ago. Direct link to Priyanka Shingrani's post “in the above example how ...” in the above example how do we calculate the value of K or Q ? As in how is it • (4 votes) Jay 8 years agoPosted 8 years ago. Direct link to Jay's post “15M is givenCo2=H2=15M” 15M is given (2 votes) Everett Ziegenfuss 8 years agoPosted 8 years ago. Direct link to Everett Ziegenfuss's post “Would adding excess react...” Would adding excess reactant effect the value of the equilibrium constant or the reaction quotient? or neither? or both? • (4 votes) KUSH GUPTA 8 years agoPosted 8 years ago. Direct link to KUSH GUPTA's post “The equilibrium constant ...” The equilibrium constant of a chemical reaction is the value of the reaction quotient when the reaction has reached equilibrium. An equilibrium constant value is independent of the analytical concentrations of the reactant and product species in a mixture, but depends on temperature and on ionic strength. (1 vote) Rajnikant Roy 6 years agoPosted 6 years ago. Direct link to Rajnikant Roy's post “How is the Reaction Const...” How is the Reaction Constant (Q) affected by change in temperature, volume and pressure ? • (4 votes) Ibeh JohnMark Somtochukwu 4 years agoPosted 4 years ago. Direct link to Ibeh JohnMark Somtochukwu's post “the reaction quotient is ...” the reaction quotient is affected by factors just the same way it affects the rate of reaction (0 votes) Eugene Choi 8 years agoPosted 8 years ago. Direct link to Eugene Choi's post “This is a little off-topi...” This is a little off-topic, but how do you know when you use the 5% rule? Cause I'm not sure when I can actually use it. • (1 vote) Eun Ju Jeong 8 years agoPosted 8 years ago. Direct link to Eun Ju Jeong's post “You use the 5% rule when ...” You use the 5% rule when using an ice table. When you plug in your x's and stuff like that in your K equation, you might notice a concentration with (2.0-x) or whatever value instead of 2.0. If the K value given is extremely small (something time ten to the negative exponent), you can elimintate the minus x in that concentration, because that change is so small it does not matter. After finding x, you multiply 0.05 to the 2.0 from 2.0-x and compare that value with what you found for x. If x is smaller than 0.05(2.0), then you're good to go! (5 votes) Vedant Walia 9 years agoPosted 9 years ago. Direct link to Vedant Walia's post “why shouldn't K or Q cont...” why shouldn't K or Q contain pure liquids or pure solids? and isn't hydrofluoric acid a pure liquid coz i remember Sal using it in the video of Heterogenous equilibrium so why did he use it? • (1 vote) Sam Woon 9 years agoPosted 9 years ago. Direct link to Sam Woon's post “The equilibrium constant ...” The equilibrium constant is a ratio of the concentration of the products to the concentration of the reactants. Keyword- concentration. While gas changes concentration after the reaction, solids and liquids do not (the way they are consumed only affects amount of molecules in the substance). Concentration of the molecule in the substance is always constant. For hydrofluoric acid, it is an aqueous solution, not a liquid, therefore it is dissolved in water (concentration can change - moles per unit volume of water). (5 votes)Want to join the conversation?
If the reaction will shift left, do the opposite.
The arrow points away from the reactants and towards the products.
1.0M or 15M?
Co2=H2=15M
