CBSE > Class 11 > Chemistry | CBSE Board | Homework Help

Ask questions which are clear, concise and easy to understand.

Ask Question

Explanation of photoelectric effect

Posted by Shagun Chadak 6 years, 7 months ago

1 answers

It is the phenomenon in which when light of suitable frequency falls on a metal surface then electron eject out it is known as photoelectric effect And read ncert

0Thank You

ANSWER

Mole concept

Posted by Mansi Sharma 6 years, 7 months ago

CBSE > Class 11 > Chemistry

1 answers

Sia ? 6 years, 7 months ago

Atoms and molecules are too small to count. To solve this problem their numbers are expressed in terms of Avogadro’s number (N_A = 6.023 10²³). Mole is the number equal to Avogadro’s number just like a dozen is equal to 12, a century means 100, a score means = 20.

Mole can be defined as a unit which represents 6.023 x10²³ particles of same matter.

A mole (symbol mol) is defined as the amount of substance that contains as many atoms, molecules, ions, electrons or any other elementary entities as there are carbon atoms in exactly 12 gm of. The number of atoms in 12 gm of is called Avogadro’s number

1Thank You

ANSWER

Convert 15 ppm into molality where glucose is the solute and water is the solvent.

Posted by Riya Mahapatra 6 years, 7 months ago

CBSE > Class 11 > Chemistry

1 answers

Riya Mahapatra 6 years, 6 months ago

Plzzz ans

0Thank You

ANSWER

Convert 1 m into mass percentage where KI is the solute and water is the solvent.

Posted by Riya Mahapatra 6 years, 7 months ago

CBSE > Class 11 > Chemistry

1 answers

Riya Mahapatra 6 years, 6 months ago

Plzz ans....

0Thank You

ANSWER

what is significant figure

Posted by Omkar Singh Omkar Singh 6 years, 7 months ago

CBSE > Class 11 > Chemistry

1 answers

Aarzoo Sharma 6 years, 7 months ago

The uncertainty in the measurement is expressed in the terms of significant figures. Significant figures are meaningful digits which are known with certainty.

0Thank You

ANSWER

Why half filled and fully filled orbitals are more stable

Posted by Ranjay Kumar 6 years, 7 months ago

CBSE > Class 11 > Chemistry

1 answers

Yogita Ingle 6 years, 7 months ago

The exactly half-filled and fully filled orbitals have greater stability than other configurations. The reason for their stability are symmetry and exchange energy.
(a) Symmetry: The half-filled and fully-filled orbitals are more symmetrical than any other configuration and symmetry leads to greater stability.
(b) Exchange Energy: The electrons present in the different orbitals of the same sub-shell can exchange their positions. Each such exchange leads to the decrease in energy known asExchange Energy. Greater the number of exchanges, greater the exchange energy and hence greater the stability. As the number of exchanges that take place in the half-filled and fully-filled orbitals is maximum, thus exchange energy is maximum and hence maximum stability.

1Thank You

ANSWER

Calculate energy of one mole of protons of radiation whose frequency is 5×10¹⁴ Hz.

Posted by Lokesh Yadav 6 years, 7 months ago

CBSE > Class 11 > Chemistry

1 answers

Sia ? 6 years, 7 months ago

Energy (E) of one photon = E = hv
where h = 6.626 {tex}\times{/tex} 10^-34 Js.
{tex}\nu{/tex} = 5 {tex}\times{/tex} 10¹⁴s^-1
{tex}\therefore E = \left( 6.626 \times 10 ^ { - 34 } \times 5 \times 10 ^ { 14 } \right){/tex}
{tex}= 3.313 \times 10 ^ { - 19 } J{/tex}
Energy of 1 mole of photon{tex}= \left( 3.313 \times 10 ^ { - 19 } J \right) \times \left( 6.022 \times 10 ^ { 23 } \mathrm { mol } ^ { - 1 } \right){/tex}= 1995.1 kJmol^-1

2Thank You

ANSWER

Describe 20 natural phenomena which can be described with the help of chemistry.

Posted by Anjali Maurya 6 years, 7 months ago

CBSE > Class 11 > Chemistry

0 answers

ANSWER

Chemical formula of sodium

Posted by Shubham Ojha 6 years, 7 months ago

CBSE > Class 11 > Chemistry

3 answers

Satyam Krishna 6 years, 6 months ago

Na(11)

0Thank You

Aadil Aadil 6 years, 7 months ago

0Thank You

Sia ? 6 years, 7 months ago

0Thank You

ANSWER

Calculate the molecular n mass of HNO 3

Posted by Riya Kumari 6 years, 7 months ago

CBSE > Class 11 > Chemistry

1 answers

Sia ? 6 years, 7 months ago

We know, Atomic mass of H = 1.001 u
Atomic mass of N = 14.01 u
Atomic mass of O = 16.0 u
Hence, molar mass of HNO₃ will be:
{tex}( 1 \times 1.001 ) + ( 1 \times 14.01 ) + ( 3 \times 16.0 ){/tex}= 63.01 u

0Thank You

ANSWER

1.5 gram of C2 H6 on complete combustion gives 4.4 gram of CO2 and 2.7 gram of H2O show that the reaction of which law of conservation of mass.

Posted by Riya Kumari 6 years, 7 months ago

CBSE > Class 11 > Chemistry

1 answers

Sia ? 6 years, 7 months ago

Hydrocarbon undergoes combustion to form carbon dioxide and water.
Molecular mass of carbon dioxide = 44 g
Mass of Carbon in 4.4 gm of carbon dioxide = {tex}\frac{12}{44} \times 4.4{/tex} = 1.2 g
Mass of Hydrogen in 2.7 gm of water = {tex}\frac{2}{18} \times 2.7{/tex} = 0.3 g
Therefore,
Total mass of Hydrogen and Carbon = (1.2 +.3)g = 1.5 g
This is the same mass before combustion.

0Thank You

ANSWER

Calculate mass of one molecule of ammonia

Posted by Gaurav Gupta 6 years, 7 months ago

CBSE > Class 11 > Chemistry

1 answers

Yogita Ingle 6 years, 7 months ago

1 mole of ammonia weighs 17 g.
1 molecule of ammonia = (17 / 6.023 x 10²³) = 2.82 x 10^-²³ g = 2.82 x 10^-²⁰ kg.

2Thank You

ANSWER

What is a quantum no and its all parts and defination also

Posted by Rahul Dalal 6 years, 7 months ago

CBSE > Class 11 > Chemistry

0 answers

ANSWER

Describe few solution for disposal of electronic wastage with the help of chemistry

Posted by Anjali Maurya 6 years, 7 months ago

CBSE > Class 11 > Chemistry

1 answers

Sia ? 6 years, 7 months ago

Recycling raw materials from end-of-life electronics is the most effective solution to the growing e-waste problem. Most electronic devices contain a variety of materials, including metals that can be recovered for future uses. By dismantling and providing reuse possibilities, intact natural resources are conserved and air and water pollution caused by hazardous disposal is avoided. Additionally, recycling reduces the amount of greenhouse gas emissions caused by the manufacturing of new products. Another benefit of recycling e-waste is that many of the materials can be recycled and re-used again. Materials that can be recycled include "ferrous (iron-based) and non-ferrous metals, glass, and various types of plastic." “Non-ferrous metals, mainly aluminum and copper can all be re-smelted and re-manufactured. Ferrous metals such as steel and iron can be also be re-used." Due to the recent surge in popularity in 3D printing, certain 3D printers have been designed (FDM variety) to produce waste that can be easily recycled which decreases the amount of harmful pollutants in the atmosphere.[80] The excess plastic from these printers that comes out as a byproduct can also be reused to create new 3D printed creations.

1Thank You

ANSWER

Definition of molarity

Posted by Prashant Kumar 6 years, 7 months ago

CBSE > Class 11 > Chemistry

2 answers

Dhama ...? 6 years, 7 months ago

It is defined as the number of moles of solute dissolve in 1 litre of solution and molarity is represent by (M)..

0Thank You

Sia ? 6 years, 7 months ago

Molarity is a concentration unit, defined to be the number of moles of solute divided by the number of liters of solution.

1Thank You

ANSWER

Show the MgO bond .

Posted by Nischay Saikia 6 years, 7 months ago

CBSE > Class 11 > Chemistry

1 answers

Sia ? 6 years, 7 months ago

1Thank You

ANSWER

How many Milligrams of bromine are present in a bottle containing 1/10kg?

Posted by Manohar Kumar 6 years, 7 months ago

CBSE > Class 11 > Chemistry

0 answers

ANSWER

Write l and m fir 4th electron in 3d orbital

Posted by Ashu Kumar 6 years, 7 months ago

CBSE > Class 11 > Chemistry

1 answers

Aditya Saha? 6 years, 7 months ago

0Thank You

ANSWER

0.30 g of an organic substance gives 0.66 g of CO2 and 0.35 g of water vapour on combustion. It's V.D.(vapour density) was 30. What will be the molecular formula of the organic substance?

Posted by Ananya Sharma 6 years, 7 months ago

CBSE > Class 11 > Chemistry

0 answers

ANSWER

5 litre of 0.4M H2so4 contains

Posted by Dinesh Bhatrai 6 years, 7 months ago

CBSE > Class 11 > Chemistry

1 answers

Priyanshu Kumar 6 years, 7 months ago

2 moles

0Thank You

ANSWER

Levis dot Structure of CH3COOH

Posted by Neetu Sharma 6 years, 7 months ago

CBSE > Class 11 > Chemistry

1 answers

Rahul Kumar 6 years, 7 months ago

We cant make the structure but you can check it on Google

0Thank You

ANSWER

Calculate the wavelength of the spectral line obtained in the spectrum of Li2+ ion when the transition takes place between two levels whose sum is 4 and the difference is 2

Posted by Ramesh Chand 6 years, 7 months ago

CBSE > Class 11 > Chemistry

1 answers

Priyanshu Kumar 6 years, 7 months ago

1032.95 A°

0Thank You

ANSWER

What is the volume of oxygen required for complete oxidation of NH3 to nitric oxide?❔❓

Posted by Ananya Sharma 6 years, 7 months ago

CBSE > Class 11 > Chemistry

0 answers

ANSWER

If we take 2 apples, how many significant figures does it have?

Posted by Divanshu Rawat 6 years, 7 months ago

CBSE > Class 11 > Chemistry

2 answers

Mayank Chouhan 6 years, 7 months ago

1 only

0Thank You

Zen Smith 6 years, 7 months ago

Infinix

0Thank You

ANSWER

What is the sequence of energies of 3s,3pand3d orbital in hydrogen atom and sodium ion

Posted by Priyanshu Negi 6 years, 7 months ago

CBSE > Class 11 > Chemistry

2 answers

Satyam Kumar 6 years, 7 months ago

3s 3p 3d

0Thank You

Praneetha Ravula 6 years, 7 months ago

3s<3p<3d

0Thank You

ANSWER

Best refrence book for prepration

Posted by Govind Singh 6 years, 7 months ago

CBSE > Class 11 > Chemistry

2 answers

Ashish Choudhary 6 years, 7 months ago

S chand

0Thank You

Farhat Shaikh Shaikh 6 years, 7 months ago

For me its Pradeep and schand

0Thank You

ANSWER

No. Of electrons in 2.8 g ethene is

Posted by Akash Gorai 6 years, 7 months ago

CBSE > Class 11 > Chemistry

1 answers

Anuska Thakur 6 years, 7 months ago

Molar mass of C2H4 (ethene) = 2×12+4×1 = 28 g Moles of ethene = Given mass / Molar mass =2.8g/28g mol^-1 =0.1 mol 1 mole = 6.022 × 10^23 atoms 0.1 mole = (6.022 ×10^23 atoms/1 mole)× 0.1 mole = 6.022 ×10^22 atoms 1 atom of C2H4 has electrons = 10 6.022×10^22 atoms of C2H4 have electrons = 6.022 ×10^22 ×10 = 6.022 ×10^22 electrons

2Thank You

ANSWER

Limiting regent

Posted by Rambo Equbal 6 years, 7 months ago

CBSE > Class 11 > Chemistry