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Ask QuestionPosted by Abhinav Baliyan 5 years ago
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Yogita Ingle 5 years ago
Due to the stable configuration, they do not accept an electron and hence they have large positive electron gain enthalpy.
An electron has to enter the next higher principal quantum level which leads to a very unstable electronic configuration.
Posted by Aman Kumar 5 years ago
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Yogita Ingle 5 years ago
According to the above equation, one mole of CH4 (16 g) on combustion gives one mole of carbon dioxide and 2 moles of water and 2 moles of water = 2 x [2 + 16] = 36 g of water.
Posted by Samina Masood 5 years ago
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Yogita Ingle 5 years ago
In the gaseous state, the atoms are widely separated therefore, interatomic forces are minimum. It is because of this reason the term ‘isolated gaseous atom’ has been included in definition of ionisation enthalpy and electron gain enthalpy.
The term ‘ground state’ here means that the atom must be present in the most stable state, i.e., the ground state. Therefore, for comparison purposes, the ionisation enthalpies and electron gain enthalpies of gaseous atoms must be determined in their respective ground states.
Posted by Good Girl ? 5 years ago
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Yogita Ingle 5 years ago
Shortest wavelength, so highest energy is for , line that drops from infinity to Lyman series.
Energy = 13.6 *(1/n-1/infinity)
Energy = 13.6 , n=1
For He+ longest wavelength is for line drop from just immediately up 3 line or 2nd exited state.
So, energy= 13.6 (Z)2 *(1/(2)2-1/(3)2)
N=2 Balmer series
N=3 longest wavelength
Z=2 He+ ion
So, energy here is 13.6*20/36
So, it is 20/36 or 5/9 times of energy of H ion so for wavelength it is 9/5 more times than H ion wavelength so,
It is 9/5 x= wavelength of He+ ion .
Posted by Vaishali Choudhary 5 years ago
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Posted by Vaishali Choudhary 5 years ago
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Yogita Ingle 5 years ago
H2O < NH3 < CH4
NH3 is better known as ammonia to us, H2O as water and CH4 as methane.
The bond angle according to the theory of VSEPR is the angle between the two electron bonds.
The number of lone pairs of electron in H2O is 2, where as it is one in NH3 and none in CH4.
Posted by Anshika Gupta 5 years ago
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Posted by Palak Yadav 5 years ago
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Yogita Ingle 5 years ago
R∞ and electron spin g-factor are the most accurately measured physical constants.
| Rydberg Constant Value,R∞ | 10973731.568508(65) m-1 |
| Rydberg Constant Value,R∞ | 1.097 x 107m-1 |
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Yogita Ingle 5 years ago
Its chemical formula is NaHCO<tt>3</tt>. Its formula consists of one sodium (Na) atom, one hydrogen (H) atom, one carbon (C) atom and three oxygen (O) atoms.
Posted by Vaishali Choudhary 5 years ago
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Meghna Thapar 5 years ago
The Carbonate (CO2−3 C O 3 2 − ) Ion
Unlike O3, though, the actual structure of CO32− is an average of three resonance structures. 2. Carbon has 4 valence electrons, each oxygen has 6 valence electrons, and there are 2 more for the −2 charge. This gives 4 + (3 × 6) + 2 = 24 valence electrons.
Posted by Vaishali Choudhary 5 years ago
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Monika Gautam 5 years ago
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Yogita Ingle 5 years ago
Molecular mass of CaCO3 = 40 × 1 + 1 × 12 + 3 × 16
= 40 + 12 + 48
= 100 u.
Posted by Sneha Kumari 5 years ago
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Gaurav Seth 5 years ago
Chemistry has a direct impact on our life and has wide range of applications in different fields. These are given below:
(A) In Agriculture and Food:
(i) It has provided chemical fertilizers such as urea, calcium phosphate, sodium nitrate, ammonium phosphate etc.
(ii) It has helped to protect the crops from insects and harmful bacteria, by the use ‘ of certain effective insecticides, fungicides and pesticides.
(iii) The use of preservatives has helped to preserve food products like jam, butter, squashes etc. for longer periods.
(B) In Health and Sanitation:
(i) It has provided mankind with a large number of life-saving drugs. Today, dysentery and pneumonia are curable due to discovery of sulpha drugs and penicillin life-saving drugs. Cisplatin and taxol have been found to be very effective for cancer therapy and AZT (Azidothymidine) is used for AIDS victims.
(ii) Disinfectants such as phenol are used to kill the micro-organisms present in drains, toilet, floors etc.
(iii) A low concentration of chlorine i.e., 0.2 to 0.4 parts per million (ppm) is used ’ for sterilization of water to make it fit for drinking purposes.
(C) Saving the Environment:
The rapid industrialisation all over the world has resulted in lot of pollution.
Poisonous gases and chemicals are being constantly released in the atmosphere. They are polluting environment at an alarming rate. Scientists are working day and night to develop substitutes which may cause lower pollution. For example, CNG (Compressed Natural Gas), a substitute of petrol, is very effective in checking pollution caused by automobiles.
(D) Application in Industry:
Chemistry has played an important role in developing many industrially ^ manufactured fertilizers, alkalis, acids, salts, dyes, polymers, drugs, soaps,
detergents, metal alloys and other inorganic and organic chemicals including new materials contribute in a big way to the national economy.
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Ankit Kumar 5 years ago
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