Answer:
0.39 mol
Explanation:
Considering the ideal gas equation as:
where,
P is the pressure
V is the volume
n is the number of moles
T is the temperature
R is Gas constant having value = 0.0821 L.atm/K.mol
At same volume, for two situations, the above equation can be written as:-
Given ,
n₁ = 1.50 mol
n₂ = ?
P₁ = 3.75 atm
P₂ = 0.998 atm
T₁ = 21.7 ºC
T₂ = 28.1 ºC
The conversion of T( °C) to T(K) is shown below:
T(K) = T( °C) + 273.15
So,
T₁ = (21.7 + 273.15) K = 294.85 K
T₂ = (28.1 + 273.15) K = 301.25 K
Using above equation as:

Solving for n₂ , we get:
n₂ = 0.39 mol
Density is mass divided by volume. Therefore, volume is mass divided by density.

Answer: half life
Explanation: Radioactive decay follows first order kinetics and the time required for the decay of a radioactive material is calculated as follows:

t= time required
k= disintegration constant
x= amount of substance left after time t
a= initial amount of substance
when one half of the sample is decayed, one half of the sample remains and t can be represented as 
at
, 


Answer: (B)
Explanation: Decreases the number of bases in the sequence.