Answer: The concentration of 
will be 
after 416 seconds have passed.
Explanation:
Expression for rate law for first order kinetics is given by:
where,
k = rate constant = 
t = age of sample = ?
a = let initial amount of the reactant = 
a - x = amount left after decay process =
The concentration of will be after 416 seconds have passed.
<h2>Total distance divided by total elapsed time gives : Average speed </h2>
Explanation:
Speed
It is the distance traveled by body with respect to time .
Its formula is Speed = distance /time
V=S/T
units : m/sec or Km/hr
Distance
It is total path traveled by body in any direction .
It unit and symbol is : S and unit = m /Km
Average speed
It is the total distance traveled by body with respect to total time taken to travel that given distance .
Average speed = total distance /total time
A.s = T.D/T.T
unit = m/sec or Km/hr
Instantaneous velocity
It is the distance traveled by body at particular instant of time ,in given direction .
Displacement
It is the shortest path traveled by body in given direction .
Answer: 
atoms of hydrogen are there in
35.0 grams of hydrogen gas.
Explanation:
According to avogadro's law, 1 mole of every substance occupies 22.4 L at STP and contains avogadro's number 
of particles.
To calculate the moles, we use the equation:
1 mole of hydrogen 
= 
atoms
17.5 mole of hydrogen = 
atoms
There are atoms of hydrogen are there in
35.0 grams of hydrogen gas.
Answer:
chemical laboratory Pune Maharashtra India
Elements are separate particles that contain the properties of only one type of element (pure substance) and an atom represents that element as the smallest non divisible particle that retains the properties of that element. Compounds can be formed by conjoining different atoms together in different ratios and shapes, so a combination of elements.
