If you get the question right i will give brainliest (HINT ITS NOT A)

Aspirin (acetylsalicylic acid, C9H8O4) is a weak monoprotic acid. To determine its acid-dissociation constant, a student dissolv

Triss [41]

Answer:

1. $3.57\times 10^{-4}$ was the $K_a$ value calculated by the student.

2. $5.93\times 10^{-4}$ was the $K_b$ of ethylamine value calculated by the student.

Explanation:

1.

The $pH$ value of Aspirin solution = 2.62

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

$[H^+]=10^{-2.62}=0.00240 M$

Moles of s asprin = $\frac{2.00 g}{180 g/mol}=0.01111 mol$

Volume of the solution = 0.600 L

The initial concentration of Aspirin = c = $\frac{0.01111 mol}{0.600 L}=0.0185 M$

$HAs\rightleftharpoons As^-+H^+$

initially

c 0 0

At equilibrium

(c-x) x x

The expression of dissociation constant :

$K_a=\frac{[As^-][H^+]}{[HAs]}$ :

$K_a=\frac{x\times x }{(c-x)}$

$=\frac{0.00240 M\times 0.00240 M}{(0.0185-0.00240 )}$

$K_a=3.57\times 10^{-4}$

$3.57\times 10^{-4}$ was the $K_a$ value calculated by the student.

2.

The $pH$ value of ethylamine = 11.87

$pH+pOH=14$

$pOH=14-11.87=2.13$

$pOH=-\log[OH^-]$

$[OH^-]=10^{-2.13}=0.00741 M$

The initial concentration of ethylamine = c = 0.100 M

$C_2H_5NH_2+H_2O\rightleftharpoons C_2H_5NH_3^{+}+OH^-$

initially

c 0 0

At equilibrium

(c-x) x x

The expression of dissociation constant :

$K_b=\frac{[C_2H_5NH_3^{+}][OH^-]}{[C_2H_5NH_2]}$ :

$K_b=\frac{x\times x}{(c-x)}$

$=\frac{0.00741\times 0.00741}{(0.100-0.00741)}$

$K_b=5.93\times 10^{-4}$

$5.93\times 10^{-4}$ was the $K_b$ of ethylamine value calculated by the student.

3 0

3 years ago

What is the concentration of each of these solutions expressed as a percent sucrose by mass?

Natali5045456 [20]

The concentration by mass means that the mass of solute in a given amount of solution. So for the a), the concentration should be 17/(17+183)*100%=8.5%. For b), the concentration should be 30/(30+300)*100%=9.09%.

7 0

4 years ago

what gases occur in the same percentages throughout the layers of the atmosphere?/A.Oxygen,Nitrogen/B.Nitrogen,Water Vapor C.Wat

Naddika [18.5K]

A. Oxygen and nitrogen. ( Just think NO nitrogen oxygen )

5 0

3 years ago

what quantity of ethylen glycol must be added to 125 g of water to raise the boiling point of 1.0 degrees celsuis

labwork [276]

Answer:

We should add 15.15 grams of ethylen glycol.

Explanation:

Step 1: Data given

Mass of water = 125 grams

Temperature change = 1.0 °C

The boiling point elevation constant, Kbp, for water is 0.5121 °C/m

Step 2: Calculate mass needed

ΔT = i* Kb * m

⇒ with i = the van't Hoff factor = 1

⇒ with Kb = 0.5121 °c/ kg/mol

⇒ with m = molality = moles / mass

ΔT = i* Kb * m ⇒ 1°C = 0.5121 °C / kg/mol * (X/0.125kg)

X = 0.2441 moles

Step 3: Calculate mass of ethylen glycol

Mass ethylen glycol = moles * molar mass

Mass ethylen glycol = 0.2441 moles * 62.068 g/mol

Mass of ethylen glycol = 15.15 grams

We should add 15.15 grams of ethylen glycol.

4 0

3 years ago

(35 points) ROCK TYPES. If you help me with this I'll love you forever

4vir4ik [10]

There are so many rock types around! Though, with all the rock types.. there are a few that we study within grade school and such. These types of rocks are,

-Igneous // Igneous rock is formed through the cooling and solidification of magma or lava.

-Sedimentary // Sedimentary rocks are types of rock that are formed by the deposition and subsequent cementation of mineral or organic particles on the floor of oceans or other bodies of water at the Earth's surface.

-Metamorphic // The original rock is subjected to heat and pressure, causing profound physical or chemical change.

-Mabel <3

4 0

4 years ago