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3 years ago

How would you measure the pH of a coloured substance such as red ink.why?

1 answer:

4 0

There are 3 possible ways of determining pH.
1. A pH meter, 2. Litmus paper/ pH test strips or 3. Titrations.

1. A pH meter works by sending a small electric current through the solution. An electrical current can only be created if there are free-moving particles such as H+ ions from an acid or OH- ions from a base. The pH meter can determine the pH by how high the conductivity is.

2. Litmus Paper or pH test strips are strips that turn a specific colour under a specific pH. This colour can then be compared to a colour chart which will tell you the pH. The downfall of this method is that the red ink will stain the strip and you will be unable to get an accurate reading.

3. A titration is the best method, if done properly, for determining pH.

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A mixture of three noble gases has a total pressure of 1.25 atm. The individual pressures exerted by neon and argon are 0.68 atm

vlabodo [156]

Add the Pressure of neon and argon that is 0.68 +0.35= 1.03
Total pressure that is 1.25 -1.03=0.22 atm

5 0

3 years ago

Read 2 more answers

How can you find the number of neutrons that are in an atom of an element

Temka [501]

Answer:

You just have to take the periodic table of the elements, take the element that interests you. Then, you look at the formula of the element, at the top left you find the number of neutrons and protons and at the bottom left you find the number of protons. Then you just have to make the number from the top left minus the number from the bottom left.

Explanation:

4 0

3 years ago

A 45.0 mL solution of 0.0450 M hydroxylamine is extracted with 125 mL of solvent. The distribution constant for the reaction is

julia-pushkina [17]

Answer:

pH = 4.5, concentration = 0.045 M.

pH = 6.5, concentration = 0.175 M.

Explanation:

The ka for the can be calculated by using the formula below;

Ka = 10^-pka = 10^-5.960 = 1.1 × 10^-6

The concentration of hydrogen ion at pH = 4.50 can be calculated as given below;

{H^+ } = 10^-4.50 = 3.2 × 10^-5 M.

(NB=> 10 in this regards means the inverse of log).

The next step is to determine the distribution coefficient which can be calculated by using the formula below;

distribution coefficient = (partition coefficient) × ka / ka + ( concentration of Hydrogen ion,H^+).

distribution coefficient =( 5 × 1.1 × 10^-6 ) / 1.1 × 10^-6 + 3.2 × 10^-5 M. = 5.5 × 10^-6/ 3.2 = 0.00000171875

The fraction remaining from the compound = 45.0 mL / 45.0 mL + (0.00000171875 × 125).

= 0.999995.

Thus, the concentration at pH = 4.5 = 0.999995 × 0.0450 M = 0.045 M

(B). pH=6.50, thus the concentration of Hydrogen ion = 10^-6.5 = 3.2 × 10^-7 M.

distribution coefficient = (partition coefficient) × ka / ka + ( concentration of Hydrogen ion,H^+).

distribution coefficient = (5 × 1.1 × 10^-6)/ 1.1 × 10^-6 + 3.2 × 10^-7 M).

distribution coefficient = 5.5 × 10^-6/ 1.42 × 10^-6 = 3.9.

Therefore, the concentration = 3.9 × 0.0450 M = 0.175 M.

8 0

3 years ago

C2H4+

klasskru [66]

Answer:

A. Theoretical yield = 3.51g

B. %yield = 75%

Explanation:

The balanced equation for the reaction is given below:

C2H4 + 3O2 —> 2CO2 + 2H2O

Molar Mass of O2 = 16 x 2 = 32g/mol

Mass of O2 from the balanced equation = 3 x 32 = 96

Molar Mass of H20 = (2x1) + 16 = 18g/mol

Mass of H2O from the balanced equation = 2 x 18 = 36g

A. From the equation,

96g of O2 produced 36g of H2O

Therefore, 9.35g of O2 will produce = (9.35 x 36)/96 = 3.51g of H2O

Therefore,theoretical yield of water (H2O) = 3.51g

B. Theoretical yield = 3.51

Actual yield = 2.63g

%yield =?

%yield = Actual yield/Theoretical yield x 100

%yield = 2.63/3.51

%yield = 75%

4 0

3 years ago

Given that the free energy of the twist-boat conformer of cyclohexane is 5.3 kcal/mol greater than that of the chair conformer,

marishachu [46]

Answer:

0.013%

Yes, it does. The answer agrees with the statement.

Explanation:

Both conformers are in equilibrium, and it can be represented by the equilibrium equation K:

K = [twist-boat]/[chair]

The free energy between them can be calculated by:

ΔG° = -RTlnK

Where R is the gas constant (8.314 J/mol.K), and T is the temperature (25°C + 273 = 298 K).

ΔG° = 5.3 kcal/mol * 4.182 kJ/kcal = 22.165 kJ/mol = 22165 J/mol

22165 = -8.314*298*lnK

-2477.572lnK = 22165

lnK = -8.946

K = $e^{-8.946}$

K = 1.30x10⁻⁴

[twist-boat]/[chair] = 1.30x10⁻⁴

[twist-boat] = 1.30x10⁻⁴[chair]

The percentage of the twist-boat conformer is:

[twist-boat]/([twist-boat] + [chair]) * 100%

1.30x10⁻⁴[chair]/(1.30x10⁻⁴[chair] + [chair]) *100%

0.013%

The statement about the conformers is that the chair conformer is more stable, and because of that is more present. So, the answer agrees with it.

3 0

3 years ago