Answer:
The atmosphere refers to the gaseous envelope of earth, comprised of variable gases with definite proportions. The layers of the earth's atmosphere are as follows-
- Troposphere- This layer starts from the ground and extends up to a height of about 10 km. Here, the temperature decreases with the increasing altitude. All the weather phenomenon takes place in this layer.
- Stratosphere- It starts from 10 km and extends up to a height of about 50 km. Here the temperature increases as the altitude increase. This is because of the presence of the ozone layer that receives the harmful UV radiation emitted from the sun.
- Mesosphere- This layer extends from a height of about 50 km to about 80 km above the earth's surface. Here, again the temperature decreases with the increasing altitude.
- Thermosphere- This layer starts from a height of about 80 km and extends up to about 500 km above the ground surface. In this region again the temperature increases with the increasing elevation.
- Exosphere- This layer ranges from about 500 km to 10,000 km above the earth's surface. Here, the temperature gradually increases with the increasing height.
This variation in temperature occurs because of the certain reason. In the troposphere and the mesosphere, the temperature decreases with height because the pressure and height are inversely proportional to each other. The stratosphere experiences increasing temperature because of the presence of the ozone layer that is responsible for holding the greenhouse gases and the harmful UV radiation. The thermosphere and the exosphere experience high temperatures because of the receiving of the direct sunlight. Due to these above reason, there occurs this temperature change in a unique pattern.
Answer:
NaCl has a smaller lattice energy compared to CaO
Explanation:
We have remember that lattice energy increases as the size of the ions in the ionic solid decreases. According to Oxford dictionary; lattice energy is "a measure of the energy contained in the crystal lattice of a compound, equal to the energy that would be released if the component ions were brought together from infinity."
We know that the larger the magnitude of charge on a cation the smaller in size the cation is and the size of anions increase from left to right in the periodic table. Hence Ca^2+<Na^+ and O^2- < Cl^-. Therefore the lattice energy of CaO is greater than that of NaCl.
Answer:
Electrostatic Van de Waals forces act between molecules to form weak bonds. The types of Van der Waals forces, strongest to weakest, are dipole-dipole forces, dipole-induced dipole forces and the London dispersion forces. The hydrogen bond is based on a type of dipole-dipole force that is especially powerful. These forces help determine the physical characteristics of materials.
