JUNDY

Most popular questions and responses by JUNDY
1. Chemistry

A solid weak acid is weighed, dissolved in water and diluted to exactly 50.00 ml. 25.00 ml of the solution is taken out and is titrated to a neutral endpoint with 0.10 M NaOH. The titrated portion is then mixed with the remaining untitrated portion and the

2. Chemistry

A weighed amount of sodium chloride is completely dissolved in a measured volume of 4.00 M ammonia solution at ice temperature, and carbon dioxide is bubbled in. Assume that sodium bicarbonate is formed until the limiting reagent is entirely used up. The

3. Chemistry

Calculate Keq for 2 moles of electron(s) in each half-reaction and a standard potential of 0.55 V.

4. Chemistry

Calculate ΔG (in kJ) at 298 K for some solid ZnF2, 0.055 M Zn2+ and 0.063 M F-(aq). I found Q to be 2.18e-4, then i implemented it into the equation deltaG=RT(lnQ). I got -20.89, but the answer is -12.2.

5. Chemistry

Concentrated hydrochloric acid is 38% HCl by weight and has a density of 1.19 g/mL. A solution is prepared by measuring 70 mL of the concentrated HCl, adding it to water, and diluting to 0.500 L. Calculate the approximate molarity of this solution from the

6. Chemistry

What is the oxidation state assigned to Cr in zinc dichromate, ZnCr2O7?

7. Chemistry

Calculate ΔGo (in J) for 2 moles of electron(s) in each half-reaction and a standard potential of 0.57 V.

8. Chemistry

Calculate the average C—C bond strength in cyclopropane (in kJ/mol). Its combustion and the experimental enthalpy of reaction are: C3H6(g) + 4.5O2(g) → 3CO2(g) + 3H2O(g) ΔHºrxn = -1,957.7 kJ/mol Since all reactants and products are in the gaseous

9. Chemistry

1)A buffer solution that is 0.10 M sodium acetate and 0.20 M acetic acid is prepared. Calculate the initial pH of this solution. The Ka for CH3COOH is 1.8 x 10-5 M. As usual, report pH to 2 decimal places. *A buffered solution resists a change in pH.*

10. Chemistry

The autodissociation of water to H+ and OH- is endothermic. At a higher temperature more of the water molecules have sufficient energy to dissociate. So, Kw is greater. At 25oC, Kw = 1.0 x 10-14. (standard Kw) At 65oC, Kw = 1.0 x 10-13. Calculate the

11. Chemistry

A reaction at 3.24 atm consumes 5.10 L of a gas adiabatically (q = 0). Calculate the change in internal energy of the system (in kJ).

12. Chemistry

There are three isotopes of phosphorus. Only one of them is stable. Calculate the binding energy per nucleon (in MeV) for P-32 (atomic mass = 31.9739 u). mass H = 1.007825 u and mass n = 1.008665 u. I multiplied the protons(15) by the mass H, and the

13. Chemistry

1)A buffer solution that is 0.10 M sodium acetate and 0.20 M acetic acid is prepared. Calculate the initial pH of this solution. The Ka for CH3COOH is 1.8 x 10-5 M. As usual, report pH to 2 decimal places. *A buffered solution resists a change in pH.*

14. Chemistry

Calculate the hydrogen ion concentration, [H+], in 0.00988 M Ba(OH)2. Careful!

15. Chemistry

A reaction at 3.24 atm consumes 5.10 L of a gas adiabatically (q = 0). Calculate the change in internal energy of the system (in kJ). I know that I have to use w=-p deltaV but how do i find the Final and Initial volumes?

16. Chemistry

1)A buffer solution that is 0.10 M sodium acetate and 0.20 M acetic acid is prepared. Calculate the initial pH of this solution. The Ka for CH3COOH is 1.8 x 10-5 M. As usual, report pH to 2 decimal places. *A buffered solution resists a change in pH.*

17. Chemistry

1.578 g of an unknown hydrocarbon (110.7 g/mol) burns in bomb calorimeter in excess oxygen. The heat capacity of the calorimeter,Cv, = 5.709 kJ/ºC and ΔT =7.995 ºC. Find ΔE for this hydrocarbon in kJ/mol.

18. Chemistry

A reaction at 2.43 atm produces 20.0 L of a gas and evolves 75.3 kJ of heat (exothermic). Calculate the change in internal energy of the system (in kJ).

A reaction at 3.24 atm consumes 5.10 L of a gas adiabatically (q = 0). Calculate the change in internal energy of the system (in kJ). I know that I have to use w=-p deltaV but how do i find the Final and Initial volumes?

20. Chemistry

A half-cell that consists of a copper wire in 1.00 M CuNO3 solution is connected by a salt bridge to a half cell containing a 1.00 M X(II) acetate solution and an electrode of metal X. The voltage of the cell is 2.00 V, with metal X as the positive

21. Chemistry

Calculate the vapor pressure of Hg at 14 oC (in atm). Hg(l) ↔ Hg(g) . . . ΔHo = 61.32 kJ and ΔSo = 98.83 J/K

22. Chemistry

Calculate the pH during the titration of 10.00 mL of 0.400 M hypochlorous acid with 0.500 M NaOH. The Ka for HOCl is 3.0 x 10-8 M. What is the pH when half the acid has been neutralized? 'I got 7.82 by using the HH formula but its wrong, help.

23. Chemistry

Calculate the pH during the titration of 10.00 mL of 0.400 M hypochlorous acid with 0.500 M NaOH. The Ka for HOCl is 3.0 x 10-8 M. What is the pH at the equivalence point? I used the HH formula and got pH=7.52+log(.222)=6.87, but its not right.

24. Chemistry

Calculate the pH during the titration of 10.00 mL of 0.400 M hypochlorous acid with 0.500 M NaOH. The Ka for HOCl is 3.0 x 10-8 M. What is the pH when half the acid has been neutralized? 'I got 7.82 by using the HH formula but its wrong, help.

25. Chemistry

Calculate the pH during the titration of 10.00 mL of 0.400 M hypochlorous acid with 0.500 M NaOH. The Ka for HOCl is 3.0 x 10-8 M. What is the pH at the equivalence point? I used the HH formula and got pH=7.52+log(.222)=6.87, but its not right.

1. Math

y=(3/2)^x

posted on April 14, 2015
2. math

Yes, that's correct.

posted on April 14, 2015
3. Chemistry

It's a limiting reagent problem. 8mol*(64.07 g/mol)=512.56 g 16mol*(34.07 g/mol)=545.12 g Therefore, SO2 is the limiting reagent. Figure out the rest

posted on April 14, 2015
4. MATH

In an arithmetic series, every term is separated from its neighbours by the same difference. So given an arithmetic sequence that starts with the first value A and has a common difference of D, the first five terms are: 1st term: A 2nd term: A + D 3rd

posted on April 14, 2015
5. Chemistry

Don't Include Oxygen in your equation and try it again.

posted on April 14, 2015
6. chemistry

M1V1 = M2V2 (.125L)(10.30M)=(x)(.500M)

posted on April 14, 2015
7. Statistics

a. 3/4 b. 4/8 c. 1/4 d. 2/7

posted on April 12, 2015
8. biology

posted on April 12, 2015
9. math

Just multiply all three dimensions to get you volume.

posted on April 12, 2015
10. Chemistry

Actually can you help me find the pH at the equilibrium point, my work: HOCl OH- I .004 .004 C -.004 -.004 E 0 0 .01*.400=.004 .008*.5=.004 I don't know what to do next...

posted on March 15, 2015
11. Chemistry

Ill post my work

posted on March 15, 2015
12. chemistry

Find the moles of ethanol and the moles of the solution, and divide ethanol by the solution.

posted on March 15, 2015