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kozerog [31]
3 years ago
8

What is the pH of a solution that contains 0.83M HCN (Ka = 4.9x10-10) and 0.64 M potassium cyanide?

Chemistry
1 answer:
oksian1 [2.3K]3 years ago
5 0

Answer:

pH= 9.2

Explanation:

Henderson hasselbach equation

pKa= log Ka= log (4.9 x 10^-10)=9.3

pH=Pka+log \frac{[A-]}{[HA]}

pH=9.3+log \frac{[CN-]}{[HCN]}

pH=9.3+log \frac{[0.64 M]}{[0.83 M]}

pH= 9.2

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The mass fractions of a mixture of gases are 15 percent nitrogen, 5 percent helium, 60 percent methane, and 20 percent ethane wi
Setler79 [48]

Answer:

Explanation:

mass fraction N₂ : He : CH₄ : C₂H₆ : : 15 : 5 : 60 : 20

mole fraction  N₂ : He : CH₄ : C₂H₆ : : 15/28 : 5/4 : 60/16 : 20/30

mole fraction  N₂ : He : CH₄ : C₂H₆ : : .5357  : 1.25 : 3.75 : .67

Total mole fractions = .5357 + 1.25 + 3.75 + 0.67 = 6.2057

mole fraction of N₂ =  .5357 / 6.2057 = .0877

mole fraction of He = 1.25 / 6.2057 = .20

mole fraction of CH₄ = 3.75 / 6.2057 = .6043

mole fraction of C₂H₆ = .67 / 6.2057 = .108

Partial pressure = total pressure x mole fraction

Partial pressure of N₂ = 1200 kPa  x .0877 = 105.24 kPa

Partial pressure of He = 1200 kPa  x .20  = 240 kPa

Partial pressure of CH₄ = 1200 kPa  x  .6043  = 725.16 kPa

Partial pressure of C₂H₆ = 1200 kPa  x .108    = 129.6 kPa

6 0
3 years ago
Find the percent composition for SF6<br> S =? %<br> F =? %
goldenfox [79]

Answer:

S = 21.92 %

F = 78.08 %

Explanation:

To find the percent composition of each element in SF6, we must find the molar mass of SF6 first.

Molar mass of SF6 = 32 + 19(6)

= 32 + 114

= 146g/mol

mass of Sulphur (S) in SF6 = 32g

mass of Fluorine (F) in SF6 = 114g

Percent composition = mass of element/molar mass of compound × 100

- % composition of S = 32/146 × 100 = 21.92%.

- % composition of F = 114/146 × 100 = 78.08%.

6 0
3 years ago
Choose the covalent compounds from the following choices Br2 MgS SO2 KF
Novosadov [1.4K]

Types of Bonds can be predicted by calculating the difference in electronegativity.

If, Electronegativity difference is,

 

                Less than 0.4 then it is Non Polar Covalent Bond

                

                Between 0.4 and 1.7 then it is Polar Covalent Bond

            

                Greater than 1.7 then it is Ionic

 

For Br₂;

                    E.N of Bromine      =   2.96

                    E.N of Bromine      =   2.96

                                                   ________

                    E.N Difference             0.00          (Non Polar Covalent Bond)


For MgS;

                    E.N of Sulfur               =   2.58

                    E.N of Magnesium      =   1.31

                                                   ________

                    E.N Difference                  1.27          (Ionic Bond)


For SO₂;

                    E.N of Oxygen      =   3.44

                    E.N of Sulfur          =   2.58

                                                   ________

                    E.N Difference             0.86          (Polar Covalent Bond)


For KF;

                    E.N of Fluorine          =   3.98

                    E.N of Potassium      =   0.82

                                                   ________

                    E.N Difference                3.16          (Ionic Bond)

Result: The Bonds in Br₂ and SO₂ are Covalent in Nature.

3 0
3 years ago
Is rubbing alcohol a mixture, compound or solutions?
Aliun [14]
Rubbing alcohol is a solution
5 0
3 years ago
Zinc and hydrochloric acid react to form zinc chloride and hydrogen gas according to
stealth61 [152]

Explanation:

Mole ratio of Zn to HCl = 1 : 2.

If we use all 2.0mol of Zn, we would need 2.0 * 2 = 4.0mol of HCl. However we only have 3.0mol of HCl.

Therefore HCl is limiting.

6 0
3 years ago
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