# constant

1. ### Constant volume combustion

I am in the process of designing a new engine and would like to get a ball park estimate of the combustion process before building the first prototype. One of the design features of the engine is true constant volume combustion. From the limited research I have performed, it seems most assume...
2. ### rydberg constant

After carrying out a spectroscopy experiment I am asked to calculate 2 values of the rydberg constant from my graph of wavenumber against 1/n2. How do I go about doing this? I have error bars so I made 2 lines (1 using the upper error and 1 using the lower errors) and then I calculated 2...
3. ### Calculate pH of a solution given the mass and the acid dissociation constant

Hi everyone! The problem: "2,50 g of ammonium chloride NH4Cl is dissolved in water and the volume of the solution is 100 cm^3. At current temperature, the Ka for NH4^+ is 5,7 * 10^-10 mol/dm^3 What pH does the solution of ammonium chloride have?" My attempt: H2O + NH4^+ <=> H3O^+ + NH3...
4. ### Which of the following is true about the equilibrium constant for this reaction?

An endothermic reaction has a positive value for ∆S. Which of the following is true about the equilibrium constant for this reaction? (A) It may be greater than 1 only at low temperatures. (B) It may be greater than 1 only at high temperatures. (C) It is greater than 1 at all temperatures...
5. ### Some chemistry questions I need help with

1. a)You put [H2] = 0,70M, [I2] = 0,70M and [HI] =1,50M. And the K value is 49. Decide the equilibrium concentrations. H2 + I2 <-> 2HI b) Which concentration HI gets inserted if the iodine concentration at a new equilibrium is 0,42Molar. The K value is still 49. c) What happens with the...
6. ### Calorimeter Constant

How do I determine the calorimeter constant from this set of data: 1. cold water mass=48.488g 2. hot water mass=43.245g 3. Initial temp cold=7.8 C, hot = 100 C 4. Final temp= 50.1 C Can someone please help? I don't know what to do.
7. ### Micheles Menton constant

Hi..... In the graph to determine the Km value, why is Vo units in umoles/min but substrate concentration is in mM? Shouldn't the Vo be umoles/min and substrate concentation be uM ? I think both the initial velocity and substrate concentration should have the same molar units because while doing...
8. ### Micheles Menton constant

Hi..... In the graph to determine the Km value, why is Vo units in umoles/min but substrate concentration is in mM? Shouldn't the Vo be umoles/min and substrate concentation be uM :confused:? I think both the initial velocity and substrate concentration should have the same molar units because...
9. ### Calculating Kc for equilibrium?

Given the chemical equilibrium: H2 + ½ S2 ⇌ H2S If the amounts of H2, S2, & H2S at equilibrium are 2, 1 & 3 moles respectively in a 10.0L flask, calculate Kc for the reaction. Write the expression for Kc for the production of 4 moles of H2. ----------------------------- The way I...
10. ### Rate Constant Problem

Question in the link. How do I go from here and get the rate constant and n values?
11. ### Equilibrium Constant

I have this question for an assignment for college and am completely stuck: "Lab measurements at 1000oC show that there are 0.12 mol of each of CO(g) and H2O(g), and 0.087 mole each of H2(g) and CO2(g) at equilibrium in a 1L container. Calculate the equilibrium constant for the reaction at...
12. ### Rate of Reaction, Activation energy and Equilibrium constant relations

Rate of reaction - How fast a reaction goes to completion Activation energy - the amount of energy to get initiate a reaction EQC - Ratio of concentrations @ equilibrium (when the forward rate = reverse rate of reaction) Just needing some clarification on a certain example. "Because Ea is...

For this pre-lab, consider the equilibrium to be... PbI2---> (Pb2+) + 2I- You mix the following: Volume of Lead Nitrate solution 3.04 mL Original concentration of Lead Nitrate solution 0.00216 M Volume of Iodide ion solution 4.69 mL Original concentration...
14. ### Thermodynamics Question: Finding Equilibrium Constant

Calculate the standard free energy change for the combustion of methanol at 25 deg. C. 2 CH3OH(l) + 3 O2(g) -> 2 CO2(g) + 4 H2O(g) My answer was -1.37E3 kJ, which was right. Now the part I need some guidance on: If instead of the theoretical 2 mol, the actual reaction uses reaction...
15. ### Determination of Equilibrium Constant for Ferric Thiocyanate

Hi everyone! I'm having trouble with this formal lab report.. and so I have taken the liberty to snap some pictures and also willing to upload and collaborate to share my work with anyone willing to help me on this. Unfortunately, my lab instructors weren't so clear in explaining everything...
16. ### Kc Equilibrium constant question

If equilibrium constant Kc for the reaction is 5.0x10^12 2NO(g)+O2(g) <=>2NO2(g) What is the value of the equilibrium constant of each of the following reactions at same temperature? a) NO(g)+1/2 O2(g) <=> NO2(g) b) 2 NO2(g) <=> 2 NO + O2(g) c) NO2(g) <=> NO + 1/2 O2(g) my work: a is...
17. ### Rate constant

Is it correct that the rate constant is 2,5 M^-1·m^-1 ? I have calculated this by reading the graph, go 1 to the right and 0,5 up. 1 to the right is equal to 25 mints and 0,5 up equals to 0,1. Then i multiply 0,5 with 25 =2,5 2,5 M^-1·m^-1 See attached file, thanks in advance is it also...
18. ### Rydberg Constant

Calculate the wavelength of the emitted photon for the first transition (highest energy) in each series. Lyman: ___________ Balmer: ___________ Paschen: ___________ * I think the wavelength should be around 100nm-900nm for each one, but when I use the equation...
19. ### henry constant

Hello all, How do we determine the solubility of oxygen in water at different temperatures....if there is a graph having temperature(in degree celsius) on X-axis and solubility (L O2/ L H2O) on Y axis...do i have to take direct values of solubility from graph OR do i have to calculate...
20. ### Help with spectrophotometric determination of equilibrium constant?

So we had this experiment, we used Fe3+ and SCN- to produce [Fe(SCN)]2+, and I know how to get the best fitting line for the calibration, but how do I get the equilibrium concentrations of the products and the reactants when determining Keq's of unknown solutions? Also, can H2O be used as a...