Ozone which is present in the stratospheric region of atmosphere is helpful for preventing harmful UV rays from reaching the surface of earth. Due to human activity, several compounds (specifically chlorofluorocarbons) are released in atmosphere. Due to inherent chemical stability of these compounds, the remain stable in lower region of atmosphere and slowly diffuse into stratosphere. On reaching the stratosphere, these compounds reacts with ozone and thereby depletes the effective concentration of ozone present in atmosphere. Hence, <span>the Montreal Protocol was signed in 1987 by major countries of the world. This aim of this protocol was to protect the stratospheric ozone layer by phasing out the production and consumption of ozone-depleting substances.</span>
Answer:
Si una reacción química libera energía, se llama reacción exotérmica. El ejemplo más común es la combustión, en la cual la energía se manifiesta en forma de calor y luz. Si, por el contrario, la reacción química requiere energía del medio para efectuarse, recibe el nombre de reacción endotérmica.
answer: D
Here is a list of the most common ways to speed up a chemical reaction
Increase the temperature (reactions that absorb energy)
Decrease the temperature (Reactions that release energy)
Answer:
NaOH
Explanation:
Look at charge Na has +1 charge and Ca has +2 charge after dissociation . Greater charge Stronger lattice. And as we need weak Lattice, so NaoH is stronger base than Ca(OH)2.
The rows are the one line of elements that goes from left to right horizontally. A column is a line of elements that goes vertically.
