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, 
Answer:
I think it is 100 if I guess
Rock is a combination of two or more minerals, and it does not possess any specific chemical composition. It is present naturally in the environment. Some examples of rocks are limestone, granite, etc.,Limestone may contain minerals like calcite and aragonite. Each mineral has a specific chemical composition with a well defined crystalline structure.
Therefore, the correct option would be a. rock as rock is the naturally occurring solid mass made up of different types of minerals.
Answer:
the relative molecular mass of hydrated iron (II) sulfate FeSO4.7H2O is 278.02
Explanation: