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4 years ago

What’s your plan for college to do or to study for

Chemistry

1 answer:

Eddi Din [679]4 years ago

8 0

Answer: I Personally plan to Participate in study groups, And get help when I need it.

(If you could make me Brainliest i would be happy)

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The pH of a 0.78M solution of 4-pyridinecarboxylic acid HC6H4NO2is measured to be 2.53.Calculate the acid dissociation constant

nika2105 [10]

Answer : The value of acid dissociation constant is, $1.1\times 10^{-5}$

Solution : Given,

Concentration pyridinecarboxylic acid = 0.78 M

pH = 2.53

First we have to calculate the hydrogen ion concentration.

$pH=-\log [H^+]$

$2.53=-\log [H^+]$

$[H^+]=2.95\times 106{-3}M$

Now we have to calculate the acid dissociation constant.

The equilibrium reaction for dissociation of (weak acid) is,

$HC_6H_4NO_2\rightleftharpoons C_6H_4NO_2^-+H^+$

initially conc. 0.78 0 0

At eqm. (0.78-x) x x

The expression of acid dissociation constant for acid is:

$k_a=\frac{[C_6H_4NO_2^-][H^+]}{[C_6H_4NO_2]}$

As, $[H^+]=[C_6H_4NO_2^-]=x$

So, $x=2.95\times 106{-3}M$

Now put all the given values in this formula ,we get:

$k_a=\frac{(x)\times (x)}{(0.78-x)}$

$k_a=\frac{(2.95\times 106{-3})\times (2.95\times 106{-3})}{(0.78-2.95\times 106{-3})}$

$K_a=1.1\times 10^{-5}$

Therefore, the value of acid dissociation constant is, $1.1\times 10^{-5}$

7 0

4 years ago

WHICH STATEMENT BEST DESCRIBES THE ARCHERS SHOOTING

vazorg [7]

Answer:

neither accurate nor precise

Explanation:

Accuracy is the ability to give the same result on different measurements made under the same conditions or to give the desired result accurately, therefore, as observed in the image, the results are not accurate, since they are all different.

They are not precise either, since the precision is the degree of agreement between the independent results of a measurement, obtained under stipulated conditions, be it repeatability, reproducibility or intermediate.

7 0

3 years ago

Read 2 more answers

At a certain temperature a 42.55% (v/v) solution of ethyl alcohol, C2H5OH, in water has a density of 0.9027 g mL-1. The density

swat32

Answer:

a. 7.187M.

b. 7.962m.

c. 0.1846

Explanation:

This solution contains 42.55mL of ethyl alcohol in 100mL of solution.

a. Molar concentration = Moles ethyl alcohol / L solution:

Moles ethyl alcohol -Molar mass: 46.07g/mol-

42.55mL * (0.7782g/mL) * (1mol / 46.07g) = 0.7187 moles ethyl alcohol

Liters solution:

100mL * (1L / 100mL) = 0.100L

Molar concentration: 0.7187mol / 0.100L = 7.187M

b. Molal concentration: Moles ethyl alcohol (0.7187moles) / kg solution

kg solution:

100mL * (0.9027g / mL) * (1kg / 1000g) = 0.09027kg

Molal concentration: 0.7187mol / 0.09027kg = 7.962m

c. Mole fraction: Moles ethyl alcohol / Moles ethyl alcohol + moles water

Moles water: -molar mass: 18.01g/mol-

Volume water = 100mL - 42.55mL = 57.45mL

57.45mL * (0.9949g/mL) * (1mol/18.01g) = 3.1736 moles water

Moles fraction:

0.7187 moles ethyl alcohol / 0.7187 moles ethyl alcohol+3.1736 moles water

= 0.1846

4 0

3 years ago

What conditions favor the formation of ionic compounds from elements? both atoms must be non metals. you must have a metal and a

astraxan [27]

You must have a metal and a non-metal

6 0

4 years ago

You have a board, wood blocks, and a toy car. Your goal is to build a ramp that sends the car as far across the floor as possibl

lakkis [162]

Answer:

<h3>The board should be placed at about an 80-88 degrees angle. </h3>

Explanation:

This will speed the car up and increase its speed as going down the ramp.

5 0

3 years ago

Read 2 more answers