Answer:
Quantity of Carbon is 4.09 gm
Explanation:
Equation of carbon reacting with oxygen to give carbon dioxide is given by
C + 
⇒ C
One mole of carbon reacts with one mole of Oxygen in this reaction to give One mole of Carbon dioxide.
So, 12 gm of carbon reacts with 32 gm of Oxygen in this reaction to give 44 gm of carbon dioxide.
15 gm of C was formed in this reaction
Oxygen used in this reaction = 
×32 = 10.91 gm ,
Thus Oxygen is in sufficient quantity in the reaction.
Now,
Carbon that must be used = ×12 = 4.09 gm.
Answer: The overall chemical reaction is exothermic is the correct statement.
Explanation: As seen from the given image, the reactants are at higher energy level and products are at lower energy level and the excess energy is released in the form of heat. These reactions are considered as exothermic reactions.
Hence, the reaction given in the image is an exothermic reaction.
The molar mass of the unknown compound is calculated as follows
let the unknown gas be represented by letter Y
Rate of C2F4/ rate of Y = sqrt of molar mass of gas Y/ molar mass of C2F4
= (4.6 x10^-6/ 5.8 x10^-6) = sqrt of Y/ 100
remove the square root sign by squaring in both side
(4.6 x 10^-6 / 5.8 x10^-6)^2 = Y/100
= 0.629 =Y/100
multiply both side by 100
Y= 62.9 is the molar mass of unknown gas
I believe c is the right answer.
