Answer : The limiting reagent is 
Solution : Given,
Moles of methane = 2.8 moles
Moles of
= 5 moles
Now we have to calculate the limiting and excess reagent.
The balanced chemical reaction is,

From the balanced reaction we conclude that
As, 2 mole of
react with 1 mole of 
So, 5 moles of
react with
moles of 
From this we conclude that,
is an excess reagent because the given moles are greater than the required moles and
is a limiting reagent and it limits the formation of product.
Hence, the limiting reagent is 
Answer:
The frequency of photon is 0.75×10¹⁵ s⁻¹.
Explanation:
Given data:
Energy of photon = 5×10⁻¹⁹ J
Frequency of photon = ?
Solution:
Formula;
E = hf
h = planck's constant = 6.63×10⁻³⁴ Js
5×10⁻¹⁹ J = 6.63×10⁻³⁴ Js ×f
f = 5×10⁻¹⁹ J / 6.63×10⁻³⁴ Js
f = 0.75×10¹⁵ s⁻¹
The frequency of photon is 0.75×10¹⁵ s⁻¹.
Explanation:
It is given that 44.45 g of hydrocarbon gas produces 2649 kJ or
of heat.
Also here, 1 lb = 453.592 g.
Therefore, amount of energy released by 453.592 g of hydrocarbon gas will be calculated as follows.

= 
It is known that 1 J =
.
Hence,
= 
= 7.508 Kwh
Thus, we can conclude that the combustion of exactly one pound of this hydrocarbon gas produce 7.508 Kwh energy.
The answer will be the gravitational force, because if we weren't in the gravity of the sun we would also be floating around with not much purpose.
Answer:
Hydrogen. Symbol: H. Atomic Weight: 1.008. ...
Magnesium. Symbol: Mg. Atomic Weight: 24.305. ...
Aluminum. Symbol: Al. Atomic Weight: 26.9815385. ...
Phosphorus. Symbol: P. ...
Chlorine. Symbol: Cl. ...
Argon. Symbol: Ar. ...
Potassium. Symbol: K. ...
Calcium. Symbol: Ca.