Answer:

Explanation:
Given that:
Half life = 30 min
Where, k is rate constant
So,
The rate constant, k = 0.0231 min⁻¹
Using integrated rate law for first order kinetics as:
Where,
is the concentration at time t
is the initial concentration
Given that:
The rate constant, k = 0.0231 min⁻¹
Initial concentration
= 7.50 mg
Final concentration
= 0.25 mg
Time = ?
Applying in the above equation, we get that:-

Answer:

Explanation:
Given
Required
Calculate the number of moles
We'll apply the following formula to solve this question

Where

The above equation is an illustration of the ideal gas law
Substitute values for p, V, R and T in:




<em>Hence, there are 243.605 moles</em>
Answer:
a. Change of state
Explanation:
Because you will see that the state has changed
<span>evaporation is the process that describe changing of water from liquid to gas</span>