the x y axis is tipped so the earth is flat
Answer:- 
Explanations:- The first reaction is combustion reaction as the hydrocarbon is burned in presence of oxygen to give carbon dioxide and water.
Second reaction is the synthesis reaction as in general a synthesis reaction looks like:

Third reaction is the decomposition reaction as it looks opposite of synthesis reaction.

In general, a single displacement reaction looks like:

Fourth reaction is single replacement reaction as bromine is replaced by chlorine.
So, the correct choice is the last reaction,
.
Answer:
102.26 moles of helium were required to Fill the Goodyear Blimp
Explanation:
To solve this question we need to use combined gas law:
PV = nRT
<em>Where P is pressure, V is volume of gas (2500L), n are moles of gas (Our incognite), R is gas constant (0.082atmL/molK) and T is absolute temperature</em>
<em />
Assuming atmospheric condition we can write P = 1atm and T = 25°C = 298.15K
Replacing:
PV/RT = n
1atm*2500L / 0.082atmL/molK*298.15K = n
<h3>102.26 moles of helium were required to Fill the Goodyear Blimp</h3>
<em />
You HAVE TO know that molarity (M) tells you the number of moles of a solute per Liters of solution.
M=mol/L
0.3M = 2.7 mol/ Volume
Volume = 2.7 mol/3.0 L
Volume = 0.9 L
In sodium there are 11 electrons
In chlorine there are 17 electrons
There are 17 protons in chlorine
There are 11 protons in sodium
I’m not sure what an octet is I study in a British system if there’s anything else you’re not sure of search the Internet it has all the answers