Answer:
D- a weak base
Explanation:
The ph scale goes from 1-10 a solution over 7ph is classified as basic. A solution thats 8.4 is only 1.4 over 7pH, making it a weak basic solution. An example of a strong base would be a solution with a pH of 9.2 (for example).
Answer:
"
" is the right answer.
Explanation:
Given:
Partial pressure of 
,
= 0.20 atm
Partial pressure of 
,
= 0.15 atm
at 
As we know,
⇒ 
By putting the values, we get
Given:
Half life(t^ 1/2) :30 years
A0( initial mass of the substance): 200 mg.
Now we know that
A= A0/ [2 ^ (t/√t)]
Where A is the mass that remains after t years.
A0 is the initial mass
t is the time
t^1/2 is the half life
Substituting the given values in the above equation we get
A= [200/ 2^(t/30) ] mg
Thus the mass remaining after t years is [200/ 2^(t/30) ] mg
<span>The answer is "D" where the number of collisions per unit area is reduced by one-half. Drawing back on the piston means the volume is increased. The pressure is reduced. There are fewer collisions when the pressure is reduced.</span>
