Reaction 3 is different from the rest and it is because a single product is synthesized.
Option 2
<u>Explanation:</u>
The reaction given in 1,2 and 4 are dissociation reaction where a single compound is getting split into two compounds. So all those three reactions are exothermic as they are breaking the bonds leading to release of energy to the surrounding. But the reaction 3 is a formation reaction, where two chemical compounds are forming a single compound.
So in this case, new bonds are formed leading to absorption of energy from the surrounding. So this is an endothermic reaction. Thus, reaction 3 is different from the rest and it is because a single product is synthesized.
Answer: 2.021 x 10^8 mm or 202,100,000
Explanation: Going from km to mm, you move the decimal place 6 times to the right.
Isomer types. The connectivity and molecular motion due to bond rotations within a molecule can result in atoms that are considered to be equivalent or non-equivalent types. For example, the six hydrogen atoms in ethane are considered to be chemically equivalent
Answer:
13. 
This is a double displacement reaction, not an acid-base reaction
14.
15. 
16.
17.
18.
19.
20.
21. 
22.
23.
24. 
Explanation:
All acid-base reaction have the same products, 
and a salt. Whit this in mind the acids would the compounds that produces the hydronium ion 
and the bases would be the compounds that produces the hydroxide ion 
C is the answer.
It says on the third picture that Bohr refined Rutherford's model by giving distinct orbits for the electrons with distinct radii.
