Answer : The value of rate constant is, 
Explanation :
First we have to calculate the rate constant, we use the formula :
Expression for rate law for first order kinetics is given by:

where,
k = rate constant = ?
t = time passed by the sample = 4.84 s
a = initial concentration = 4.17 M
a - x = concentration after time 4.84 s = 3.56 M
Now put all the given values in above equation, we get


Therefore, the value of rate constant is, 
amount of time the two substances are in contact. area in contact between the two substances. specific heat of the material that makes up the substances. the density of the two substances in contact.
Answer: False
Explanation:
4C2H6 + 7O2 --> 6H2O + 4CO2
8 Carbons on the reactant side, but 4 Carbons on the Product
24 Hydrogens on Reactant, 12 H on product
But Oxygen is balanced, 14 on each side
Answer:
in the wire last one is right