Answer:
Bombardment by asteroids
Explanation:
All of the other ones explain themselves
AgNO₃+NaCl⇒AgCl+NaNO₃
<h3>Further explanation</h3>
Double-Replacement reactions. Happens if there is an ion exchange between two ion compounds in the reactant to form two new ion compounds in the product
Reaction
AB + CD⇒AD + CB
So for the option :
1. synthesis/combination reaction
2. decomposition reaction
3. double replacement reaction
4. single replacement reaction
Wikipedia
Blogs from random people
<u>Answer:</u> The fugacity coefficient of a gaseous species is 1.25
<u>Explanation:</u>
Fugacity coefficient is defined as the ratio of fugacity and the partial pressure of the gas. It is expressed as 
Mathematically,

Partial pressure of the gas is expressed as:

Putting this expression is above equation, we get:

where,
= fugacity coefficient of the gas
= fugacity of the gas = 25 psia
= mole fraction of the gas = 0.4
P = total pressure = 50 psia
Putting values in above equation, we get:

Hence, the fugacity coefficient of a gaseous species is 1.25
The separation of molecules. I wouldn't put that if i were you.