There are four main types of air pollution sources:
<span>mobile sources – such as cars, buses, planes, trucks, and trainsstationary sources – such as power plants, oil refineries, industrial facilities, and factoriesarea sources – such as agricultural areas, cities, and wood burning fireplaces<span>natural sources – such as wind-blown dust, wildfires, and volcanoes........hope i helped</span></span>
Answer: 
Explanation:
Heat of reaction or enthalpy change is the energy released or absorbed during the course of the reaction.
It is calculated by subtracting the enthalpy of reactants from the enthalpy of products.

= enthalpy change = ?
= enthalpy of products
= enthalpy of reactants
For the given reaction :



<em>Thermal energy</em> is the sum of the kinetic and potential energies of all the particles in an object.
Assume that you have 250 gL of water and 1 kg of water at the same temperature.
Then, each water molecule has the same kinetic energy.
The larger sample contains four times as many molecules, so it contains four times as much thermal energy.
Thus, thermal energy is directly proportional to mass.
In symbols, <em>KE </em>∝ <em>m</em> or <em>KE = km</em>.
The graph of a direct proportion is a <em>straight line passing trough the origin</em>.
It should look something like the graph below.
The brain. The brain tells the body what to do same way the nucleus does for the cell.