Search found 257 matches

by Dhamnekar Winod
Fri Feb 05, 2021 6:30 am
Forum: Chemistry forum
Topic: Bond dissociation energies
Replies: 2
Views: 1502

Re: Bond dissociation energies

I got answer to this question.

The figures given in the parenthesis against each bond dissociation energies are Uncertainty.

e.g \(Al - Al 186 \pm 9kJ/mol\)
by Dhamnekar Winod
Fri Feb 05, 2021 5:59 am
Forum: Chemistry forum
Topic: Two step mole conversions
Replies: 4
Views: 2019

Re: Two step mole conversions

I am sorry. I computed for CH₃N₂. I shall edit my answer now.
Thanks for finding out error in the computation
by Dhamnekar Winod
Fri Feb 05, 2021 5:19 am
Forum: Chemistry forum
Topic: Two step mole conversions
Replies: 4
Views: 2019

Re: Two step mole conversions

A sample of Calcium Nitride Ca3N2having a mass 6.78 grams have 2.75e22 atoms which is= 0.0457 mole.
by Dhamnekar Winod
Fri Feb 05, 2021 4:23 am
Forum: Chemistry forum
Topic: Hess's Law
Replies: 5
Views: 2186

Re: Hess's Law

I got detailed answer to this question given by chemistry professor as follows: (9) H_2SO_4 + 2H_2O \rightarrow H_2SO_4\cdot 2H_2O \Delta H= 116.7 kJ/mol Reverse(10)H_2SO_4\cdot2H_2O \rightarrow H_2SO_4\cdot H_2O + H_2O \Delta H =-38.56 kJ/mol Change sign Adding these two reactions to obtain... H_2S...
by Dhamnekar Winod
Fri Feb 05, 2021 2:49 am
Forum: Chemistry forum
Topic: How to identify all these 4 unknown reactions?🤔
Replies: 0
Views: 12766

How to identify all these 4 unknown reactions?🤔

How to identify all these 4 unknown reactions?
identify reactions.png
identify reactions.png (52.5 KiB) Viewed 12766 times
by Dhamnekar Winod
Fri Feb 05, 2021 12:26 am
Forum: Chemistry forum
Topic: Bond dissociation energies
Replies: 2
Views: 1502

Bond dissociation energies

What is the meaning of figures given in brackets in the attached page for bond dissociation energies?
by Dhamnekar Winod
Tue Feb 02, 2021 5:08 am
Forum: Chemistry forum
Topic: Hess's Law
Replies: 5
Views: 2186

Re: Hess's Law

So, we get 116.7 - 38.56 = 78.14. (Unit of energy is unknown).
How can we say confidently without any experiment that this aforesaid answer is correct? :? :?: :o
by Dhamnekar Winod
Mon Feb 01, 2021 11:35 pm
Forum: Chemistry forum
Topic: Hess's Law
Replies: 5
Views: 2186

Hess's Law

Germain Henri Hess reported calorimetric analyses of a number of reactions of sulfuric acid and several of its hydrates. Among them were (9) H_2SO_4 + 2 H_2O \rightarrow H_2SO_4.2H_2O (10) H_2SO_4.H_2O + H_2O \rightarrow H_2SO_4.2H_2O (The numbering is from Hess's paper.) He reported that the heat e...
by Dhamnekar Winod
Sat Jan 30, 2021 10:33 am
Forum: Chemistry forum
Topic: Computing pH of 1 L solution containing acetic acid and Sodium acetate after adding HCl.
Replies: 3
Views: 1567

Re: Computing pH of 1 L solution containing acetic acid and Sodium acetate after adding HCl.

Hello,
Consider the volume of HCl is negligible. Would you show me your computations of pH in the both cases, if possible?
by Dhamnekar Winod
Sat Jan 30, 2021 9:55 am
Forum: Chemistry forum
Topic: Computing pH of 1 L solution containing acetic acid and Sodium acetate after adding HCl.
Replies: 3
Views: 1567

Computing pH of 1 L solution containing acetic acid and Sodium acetate after adding HCl.

A 1.0 L solution contains 0.2 M CH3COOH and 0.2 M CH3COONa. What is the pH after 0.05 M of HCl has been added to the solution? What the effect would be on adding the HCl to 1 L containing 0.2 mol of CH3COOH alone (not a buffer)? In other words, What is the pH of 1 L solution containing 0.2 M of CH3C...
by Dhamnekar Winod
Fri Jan 29, 2021 9:29 am
Forum: Chemistry forum
Topic: Why does water freeze in a pan of alcohol due to blowing air over it?
Replies: 1
Views: 1031

Why does water freeze in a pan of alcohol due to blowing air over it?

If you put a very shallow dish of water in a pan of alcohol and blow air over it by means of a electric fan, the water will freeze...why?

What is the answer?
by Dhamnekar Winod
Thu Jan 28, 2021 10:57 pm
Forum: Chemistry forum
Topic: Equilibrium test question
Replies: 1
Views: 1091

Equilibrium test question

Br_2(l) + H_2O (l) \rightleftharpoons Br^-(aq)+ BrO^- (aq) + 2H^+ If sodium hydroxide is added to the mixture, what will happen to the position of equilibrium? 1)The equilibrium shifts to the right. 2)The position of the equilibrium remains unchanged. 3)The equilibrium shifts to the left. Answer pr...
by Dhamnekar Winod
Thu Jan 28, 2021 10:20 am
Forum: Chemistry forum
Topic: Computing percentage concentration of H2SO4
Replies: 3
Views: 1623

Re: Computing percentage concentration of H2SO4

How to compute specific gravity of 5.3 % w/w \(H_2SO_4 ? \) I know specific gravity =\(\frac{density_{substance}}{density_{water}}\)

Density of water=1.
Density of \(H_2SO_4=1.8302/cm^3\)

How to use specific gravity of 5.3% w/w \(H_2SO_4\) for computing volume of the solution?
by Dhamnekar Winod
Thu Jan 28, 2021 8:07 am
Forum: Chemistry forum
Topic: Computing percentage concentration of H2SO4
Replies: 3
Views: 1623

Computing percentage concentration of H2SO4

175.0 g pure H_2O was placed in a beaker and thereafter 9.80 g pure H_2SO_4 was added and stirred. What is the total volume of the solution and what is the percentage concentration of H_2SO_4 in the solution? My answer: 1.0 ml= 1.0 g H_2O Hence 175.0 g pure H_2O =175.0 ml H_2O 9.80 g H_2SO_4 =5.36 m...
by Dhamnekar Winod
Wed Jan 27, 2021 9:43 am
Forum: Chemistry forum
Topic: Determining calorimeter constant
Replies: 1
Views: 1098

Determining calorimeter constant

https://www.chemteam.info/Thermochem/Video-calorimeter-constant-02.mp4 My answer to the problem in the above video: If the constant were zero, the final temperature of the water would be 45.0 °C. So the amount of heat used by the calorimeter to heat from 21.3 to 43.3 is: (50.0) (4.184) (1.7) = 355.6...