Ask a Doubt
Request a call back

Join NOW to get access to exclusive study material for best results

CBSE Class 10 Answered

Calculate the heat of formation of water?
Asked by | 26 Feb, 2008, 04:07: PM
Expert Answer

H reacts with oxygen to form water. Calculate the heat of formation of water?

The bond energy of H-H ,  O=O and O-H are 435KJ 495KJ 460KJ respectively

435 + 1/2 495 = 682.5 is the energy absorbed to break existing bonds in reactants and 2x460=920 is the energy evolved in formation of 2 O-H bonds in water. heat of formation of water= -237.5kJ

Answered by | 02 Mar, 2008, 07:09: PM
Multiple Choice Questions Practice Test Subjective Questions Webinar Subjective Questions Pre Board Assessment

Concept Videos

Application Videos

Answered Unanswered My Questions My Answers
CBSE 10 - Chemistry
         C5H8O2+         NaH+    HCl→____C5H12O2+         NaCl balancing the equation  
Asked by kashviS.shah | 14 Sep, 2022, 11:27: PM
ANSWERED BY EXPERT
CBSE 10 - Chemistry
Hi sir, Good evening  I have one doubt regarding to Hybridisation. In the hybridisation phenomenon, only the central atom's orbitals get hybridized and form hybrid orbitals then what about the surrounding atom's orbitals they won't get hybridized. For example in a BF3 molecule what about Fluorine hybridization and in a CO2 molecule what about the oxygen atom's orbital hybridization?  Please give clarity on this sir. Thank you sir.
Asked by jafferkhan55 | 14 Sep, 2022, 06:40: AM
ANSWERED BY EXPERT
CBSE 10 - Chemistry
10 examples of enrichment of ore  
Asked by 83dimplejain29 | 01 Sep, 2022, 03:04: PM
ANSWERED BY EXPERT
CBSE 10 - Chemistry
The chemical reaction between MnO2 and HCl is an example of?
Asked by ten.foundation | 29 Aug, 2022, 07:53: PM
ANSWERED BY EXPERT
CBSE 10 - Chemistry
Mention the type of reaction that take place on heating lead nitrate crystal
Asked by Shadm4242 | 20 Aug, 2022, 12:35: PM
ANSWERED BY EXPERT
CBSE 10 - Chemistry
1.A farmer has grown the petunia flowers on his field. He observed that the colour of the flowers started changing from blue to reddish purple. • What could be the possible reason for the change in colour? ⚫ What role is played by petunia flowers? • Suggest any two substances playing the same role in the field of agriculture. • What should be added by the farmer to treat the soil? What type of reaction will take place during treatment of soil? 2. A metal X reacts with HCI to liberate gas A but its compound Y releases gas B with HCI along with the salt CaCl,. Name the metal X. • Identify gas A and how will you test for it? ⚫ Name the salt Y and give its molecular formula. • Identify gas B and how will you test for it? What type of reaction takes place when X reacts with HCI? 3. A sodium salt 'A' is used while baking a cake. It makes the cake fluffy and spongy due to the release of gas 'B'. Identify salt 'A'. ⚫ What is the common name of this salt? ⚫ Which gas is released during the process? • How will you test for gas 'B'? 4. Anita's mother asked her to store the pickle in some bowl. She kept the pickle in a brass bowl. Was she right in doing that? Why or why not?
Asked by 9414612ji | 19 Aug, 2022, 08:25: AM
ANSWERED BY EXPERT
CBSE 10 - Chemistry
solve this
Asked by Sunita | 21 Jul, 2022, 10:18: AM
ANSWERED BY EXPERT
CBSE 10 - Chemistry
solve this
Asked by labheshvaidya | 20 Jul, 2022, 10:59: AM
ANSWERED BY EXPERT
CBSE 10 - Chemistry
How to Identify the solid liquid gaseous and aqueous states
Asked by ansheera3236 | 11 Jul, 2022, 05:05: PM
ANSWERED BY EXPERT
CBSE 10 - Chemistry
Balance the following equation—
Asked by saharupa28041 | 30 Jun, 2022, 11:29: PM
ANSWERED BY EXPERT
My Class Videos Tests ₹ Plans Ask a Doubt
Season Break Offer!
Get 60% Flat off instantly.
Avail Now
×