1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Misha Larkins [42]
3 years ago
13

The ph of 0.255 m hcn is 4.95. What is the value of ka for hydrocyanic acid?

Chemistry
1 answer:
Lera25 [3.4K]3 years ago
5 0

Answer:

Ka = 4.9 X 10^-9

Explanation:

when the pH  is 4.95

the [H+] = 10^-4.95

[H+] = 1.122 e-5

since the equilibrium equation is:

HCN <=> 1 mole H+  &  1 mole CN-

then

[H+] = [CN-]

when

HCN <=>  H+  &   CN-

Ka = [ H+]  [CN-]  / [HCN]

Ka = [ 1.122 e-5]  [ 1.122 e-5]  / [0.255]

Ka = 1.256 e-10 / 0.255

Ka = 4.94 e-9

which rounds off to 2 sig figs into

Ka = 4.9 X 10^-9

======================

p.s. it was the pH pf 4.95 that limited the calculations to 2 sig figs

You might be interested in
Now they feel it is best to have you identify an unknown gas based on its properties. Suppose 0.508 g of a gas occupies a volume
pishuonlain [190]

Answer: Option (b) is the correct answer.

Explanation:

The given data is as follows.

             mass = 0.508 g,               Volume = 0.175 L

             Temperature = (25 + 273) K = 298 K,       P = 1 atm

As per the ideal gas law, PV = nRT.

where,  n = no. of moles = \frac{mass}{\text{molar mass}}

Hence, putting all the given values into the ideal gas equation as follows.

               PV = \frac{mass}{\text{molar mass}} \times RT            

           1 atm \times 0.175 L = \frac{0.508 g}{\text{molar mass}} \times 0.0821 L atm/ K mol \times 298 K  

                            = 71.02 g

As the molar mass of a chlorine atom is 35.4 g/mol and it exists as a gas. So, molar mass of Cl_{2} is 70.8 g/mol or 71 g/mol (approx).

Thus, we can conclude that the gas is most likely chlorine.

4 0
3 years ago
This chemical equation represents the burning of methane, but the equation is incomplete. What is the missing coefficient in bot
Zolol [24]
CH4+(x)O2=CO2 +(Y)H2O
C=1 +H=4 +O=? = C=1 +O=2+? +H=?
H=4>>Y=2
C=1 +H=4 +O=? = C=1 +O=(2+2) +H=4
C=1 +H=4 +O=4 = C=1 +O=4 +H=4
O=4>>X=2
CH4+(2)O2 =CO2 +(2)H2O

6 0
3 years ago
Read 2 more answers
sugar taken in a boiling tube is strongly heated. a) write the procedure of this experiment . b) which are the products obtained
Tpy6a [65]

Answer:

chemical changes

Explanation:

A chemical change is one in which a new kind of matter is formed. It is always accompanied by energy changes. The process is not easily reversible and hence, it is a permanent procedure.

Burning of charcoal produces a new kind of produces in the combustion process.

Both heating of copper(ii)carbonate strongly and zinc oxide will lead to a decomposition reaction in which new compounds are formed.

6 0
2 years ago
Which will result in positive buoyancy and cause the object to float?
Darina [25.2K]
I would say D. Let me know if i am wrong.
3 0
3 years ago
Read 2 more answers
In the third period of the periodic table sodium is followed by magnesium aluminum silicon and phosphorus which of these element
wariber [46]
Answer:
            Phosphorous has the smallest atomic size.

Explanation:
                   As we know these elements belong to same period means there valence shell is the same. So moving from left to right along the period the shell number remains constant but the number of protons and electrons increases. So, due to increase in number of protons the nuclear charge increases hence attracts the valence electrons more effectively resulting in the decrease of atomic size.

Elements and their atomic radius are as follow,

<span><span>Magnesium          0.160 nm
</span><span>
Aluminium           0.130 nm
</span><span>
Silicon                  0.118 nm
</span><span>
Phosphorus         <span>0.110 nm</span></span></span>
6 0
3 years ago
Other questions:
  • A patient being treated for thyroid cancer is to receive a dose of iodine-131. The typical dose is 4.5 uCi/kg of body weight.
    8·1 answer
  • You know that energy cannot be created or destroyed, so what happens to it?
    5·2 answers
  • What is the correct interpretation of the mole ratios for the elements in
    6·2 answers
  • At what temperature will water change from a solid to a liquid (melt)?
    5·2 answers
  • When table salt is placed in water and stirred it dissolves and a clear liquid is obtained. This process is a
    12·1 answer
  • What is the speed of a wave with a frequency of 2 Hz and a wavelength of 87 m
    11·2 answers
  • Rotation is the spin of a body on its axis. Revolution is the movement of one body around another in an ellipse-shaped path call
    13·1 answer
  • What happens to a glass of sugar solution when sugar is added to it?
    8·1 answer
  • What effect does an increase in carbon dioxide (CO 2 ) have on the concentration of hydrogen ions (H^ + ) in the blood?
    11·1 answer
  • Why is the first one (A) correct?
    11·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!