Single replacement and I know that for sure if you need me to explain i can but its Single replacement <span />
Answer:

Explanation:
Expanded Structure shows all the atoms and the bonds of the molecule. It is important to remember, each Carbon molecule have four bonds, while the Hydrogen just one. So:
1)
Pentene. 5 Carbon molecules, 10 Hydrogen molecules. It's an isomer, so this organic compound has multiple arrangements.
2) 
Ethane. 2 Carbon and 6 Hydrogen Molecules. Check it below.
The answer is Doppler Radar. Hope this helps!
Answer:
. A homogeneous mixture of a solid in a gas