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zvonat [6]
2 years ago
11

A 20.0 mL of 0.27 M solution of the salt NaA has a pH of 8.70.

Chemistry
1 answer:
zlopas [31]2 years ago
3 0

Answer:

a) 3.969

b) 3.489

Explanation:

a) Calculate the pk, value of the acid HA

PH of salt hydrolysis

P^{H} = 1/2 ( pkw + pka + logC )

8.7 * 2 =  14 + log ( 0.27 )  + Pka

∴ Pka = 3.9686  ≈  3.969

b) Calculate the PH of a solution containing 0.3 M HA and 0.1 M NaA

PH = Pka + log ( salt / acid )

    = 3.9686 + log ( 0.1 / 0.3 )

    =  3.9686 - 0.48  = 3.489

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Base A dissociates 25% in water. Base B dissociates 50%. Base C dissociates
torisob [31]

Answer:Base A is the weakest conductor electricity

Explanation:

Dissociation is a factor that affects electrical conductivity. The greater the percentage of dissociation for bases the stronger the conductivity of electricity.

Given that

Base A dissociates 25% in water

Base B dissociates 50%.

Base C dissociates 75%

We can conclude that  Base A is the weakest conductor oelectricity since it has the lowest percentage of dissociation.

5 0
2 years ago
When the potential difference across a lamp is 3.3V the current is 0.15 calculate the resistance of the lamp and give the unit
marissa [1.9K]

Answer:

22Ω

Explanation:

Given parameters:

Potential difference  = 3.3V

Current  = 0.15A

Unknown:

Resistance  = ?

Solution:

According to ohm's law, potential difference, current and resistance are related by the expression below;

             V = I R

where V is the voltage

           I is the current

          R is the resistance

          3.3 = 0.15 x R

             R = \frac{3.3}{0.15}   = 22Ω

6 0
2 years ago
Assume the atmospheric pressure is 1 atm but the actual pressure is higher than 1 atm how will this error affect the calculated
ozzi
Answer : When we consider the atmospheric pressure as 1 atm then according to the ideal gas equation we can find out the molar mass of any unknown by this formula ;

PV=nRT

so if the pressure increases than 1 atm then we can see from the above equation that it will result in greater value for the number of moles (n) in the above equation.

While n = m/M where m is mass of the unknown in g and M is molecular mass.

So, if pressure is higher then it will result in molar mass of unknown which is much smaller.
6 0
3 years ago
0.5mol/dm3 hydrochloric acid is added gradually to a flask containing 20cm3 of 2 mol/ dm3 sodium hydroxide solution.
sweet-ann [11.9K]

Answer:

The answer is B which is 40

7 0
2 years ago
The ideal gas constant, R has several different values that could be used. Which quantity causes these differences?
Vera_Pavlovna [14]

Answer:

The answer is A

Explanation:

6 0
2 years ago
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