<u>Answer:</u> The average rate of the reaction is 
<u>Explanation:</u>
To calculate the molarity of hydrogen gas generated, we use the equation:

Moles of hydrogen gas = 
Volume of solution = 250 mL = 0.250 L (Conversion factor: 1 L = 1000 mL)
Putting values in above equation, we get:

Average rate of the reaction is defined as the ratio of concentration of hydrogen generated to the time taken.
To calculate the average rate of the reaction, we use the equation:

We are given:
Concentration of hydrogen generated = 0.1564 M
Time taken = 20.0 minutes
Putting values in above equation, we get:

Hence, the average rate of the reaction is 
(2.03x10^22)/(6.02x10^23) = .033721 mol Li
I hope this helps, if not, i am sorry
Balance Chemical Equation for this reaction is,
2 CH₄ + O₂ → 2CH₃OH
According to this eq, 22.4 L (1 moles) of Oxygen requires 44.8 L (2 mole) CH₄ for complete reaction.
So, the volume of CH₄ required to consume 0.66 L of O₂ is calculated as,
22.4 L O₂ required to consume = 44.8 L CH₄
0.660 L O₂ will require = X L of CH₄
Solving for X,
X = (44.8 L × 0.660 L) ÷ 22.4 L
X = 1.320 L of CH₄
Result:
1.320 L of CH₄ <span>gas is needed to react completely with 0.660 L of O</span>₂<span> gas to form methanol (CH</span>₃OH<span>).</span>
Last one cuz it stay in the air for a while then swings making it kinetic