<u>Answer:</u> The chemical equation is written below.
<u>Explanation:</u>
Combustion reaction is defined as the chemical reaction in which a hydrocarbon reacts with oxygen gas to produce carbon dioxide gas and water molecule.

The chemical equation for the combustion of ethyl chloride follows:

We are given:
When 4 moles of ethyl chloride is burnt, 5145 kJ of heat is released.
For an endothermic reaction, heat is getting absorbed during a chemical reaction and is written on the reactant side.

For an exothermic reaction, heat is getting released during a chemical reaction and is written on the product side

So, the chemical equation follows:

Hence, the chemical equation is written above.
Answer:
The atomic mass of second isotope is 7.016
Explanation:
Given data:
Average Atomic mass of lithium = 6.941 amu
Atomic mass of first isotope = 6.015 amu
Relative abundance of first isotope = 7.49%
Abundance of second isotope = ?
Atomic mass of other isotope = ?
Solution:
Total abundance = 100%
100 - 7.49 = 92.51%
percentage abundance of second isotope = 92.51%
Now we will calculate the mass if second isotope.
Average atomic mass of lithium = (abundance of 1st isotope × its atomic mass) +(abundance of 2nd isotope × its atomic mass) / 100
6.941 = (6.015×7.49)+(x×92.51) /100
6.941 = 45.05235 + (x92.51) / 100
6.941×100 = 45.05235 + (x92.51)
694.1 - 45.05235 = (x92.51)
649.04765 = x
92.51
x = 485.583 /92.51
x = 7.016
The atomic mass of second isotope is 7.016
Answer : The grams of
consumed is, 89.6 grams.
Solution : Given,
Mass of
= 265 g
Molar mass of
= 80 g/mole
Molar mass of
= 28 g/mole
First we have to calculate the moles of
.

The given balanced reaction is,

from the reaction, we conclude that
As, 1 mole of
produces from 1 mole of 
So, 3.2 moles of
produces from 3.2 moles of 
Now we have to calculate the mass of 


Therefore, the grams of
consumed is, 89.6 grams.
Answer: C
I hope this helped you
Answer:
0.74 grams of methane
Explanation:
The balanced equation of the combustion reaction of methane with oxygen is:
it is clear that 1 mol of CH₄ reacts with 2 mol of O₂.
firstly, we need to calculate the number of moles of both
for CH₄:
number of moles = mass / molar mass = (3.00 g) / (16.00 g/mol) = 0.1875 mol.
for O₂:
number of moles = mass / molar mass = (9.00 g) / (32.00 g/mol) = 0.2812 mol.
- it is clear that O₂ is the limiting reactant and methane will leftover.
using cross multiplication
1 mol of CH₄ needs → 2 mol of O₂
??? mol of CH₄ needs → 0.2812 mol of O₂
∴ the number of mol of CH₄ needed = (0.2812 * 1) / 2 = 0.1406 mol
so 0.14 mol will react and the remaining CH₄
mol of CH₄ left over = 0.1875 -0.1406 = 0.0469 mol
now we convert moles into grams
mass of CH₄ left over = no. of mol of CH₄ left over * molar mass
= 0.0469 mol * 16 g/mol = 0.7504 g
So, the right choice is 0.74 grams of methane