All categories

4 years ago

Calculate the equilibrium concentration of hc2o4− in a 0.20 m solution of oxalic acid.

1 answer:

3 0

For the first dissociation of H2C2O4 ↔ H+ + HC2O4-, pKa = 1.23
Ka = 10^-1.23
Ka = 0.0589

Ka = [H+] [ HC2O4-] / [H2C2O4]
Call [H+] = X which will also = [HC2O4-] and that [H2C2O4] = (0.2-X )
So we can write:
0.0589 = X² / (0.2-X)
X² = 0.0589( 0.2 - X)
X² = 0.01178 - 0.0589X
X² + 0.0589X - 0.01178 = 0
Solve quadratic for X: Positive root = 0.083

The molar concentration of HC2O4- at equilibrium = 0.083M

This is from yahoo. Credit to Trevor H

You might be interested in

A chemist must prepare of hydrochloric acid solution with a pH of at . He will do this in three steps: Fill a volumetric flask a

Eva8 [605]

Answer:

1.7 mL

Explanation:

A chemist must prepare 550.0 mL of hydrochloric acid solution with a pH of 1.60 at 25 °C. He will do this in three steps: Fill a 550.0 mL volumetric flask about halfway with distilled water. Measure out a small volume of concentrated (8.0 M) stock hydrochloric acid solution and add it to the flask. Fill the flask to the mark with distilled water. Calculate the volume of concentrated hydrochloric acid that the chemist must measure out in the second step. Round your answer to 2 significant digits.

Step 1: Calculate [H⁺] in the dilute solution

We will use the following expresion.

pH = -log [H⁺]

[H⁺] = antilog - pH = antilog -1.60 = 0.0251 M

Since HCl is a strong monoprotic acid, the concentration of HCl in the dilute solution is 0.0251 M.

Step 2: Calculate the volume of the concentrated HCl solution

We want to prepare 550.0 mL of a 0.0251 M HCl solution. We can calculate the volume of the 8.0 M solution using the dilution rule.

C₁ × V₁ = C₂ × V₂

V₁ = C₂ × V₂/C₁

V₁ = 0.0251 M × 550.0 mL/8.0 M = 1.7 mL

3 0

3 years ago

What is the density of an object if its mass is 10 g and a volume of 2 mL?

Lilit [14]

Hi there! Let's solve this problem shall we!

⠀Volume = 10g

Mass = 2 mL

In this specific problem, they are asking us to find the density of the object. So, using the information given to us (volume and mass), let's solve the problem!

Now, if you remember, D = M ÷ V

So, let's fill in the blanks!

D = Our unknown value

M = 2mL

V = 10g

Here is the filled out formula:

D = M ÷ V

D = 2mL ÷ 10g

D = 5 g/mL

*Make sure you put the units for your final solution!*

4 0

2 years ago

Comparing the 2-bromobutane + methoxide and 2-bromobutane + t-butoxide reactions, choose the statements that BEST describe the d

Elina [12.6K]

Answer:

an increase in 1-butene was observed when t-butoxide was used

Explanation:

When a base reacts with an alkyl halide, an elimination product is formed. This reaction is an E2 reaction.

Here we are to compare the reaction of two different bases with one substrate; 2-bromobutane. Both reactions occur by the E2 mechanism but follow different transition states due to the size of the base.

The Saytzeff product, 2-butene, is obtained when the methoxide is used while the non Saytzeff product, 1-butene, is obtained when t-butoxide is used.

The Saytzeff rule is reliable in predicting the major products of simple elimination reactions of alkyl halides given the fact that a small/strong bases is used for the elimination reaction. Therefore hydroxide, methoxide and ethoxide bases give similar results for the same alkyl halide substrate. Bulky bases such as tert-butoxide tend to yield a higher percentage of the non Saytzeff product and this is usually attributed to steric hindrance.

8 0

3 years ago

The sea water has 8.0x10^-1 cg of element strontium. Assuming that all strontium could be recovered, how many grams of strontium

PilotLPTM [1.2K]

984 grams of strontium will be recovered from 9.84x10^8 cubic meter of seawater.

Explanation:

From the question data given is :

volume of strontium in sea water= 9.84x10^8 cubic meter

(1 cubic metre = 1000000 ml)

so 9 .84x10^8 cubic meter

$\frac{9 .84x10^8}{1000000}$ = 984 ml.

density of sea water = 1 gram/ml

from the formula mass of strontium can be calculated.

density = $\frac{mass}{volume}$

mass = density x volume

mass = 1 x 984

= 984 grams of strontium will be recovered.

98400 centigram of strontium will be recovered.

Strontium is an alkaline earth metal and is highly reactive.

4 0

3 years ago

What is plasma and how /why does it form

Hunter-Best [27]

Answer:

I can answer 1 part Plasma is the fluid part of blood at least in bio(srry if it doesnt work)

Explanation:

7 0

3 years ago