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
Answer:
[H⁺] = 3.98×10⁻⁷ M
Explanation:
Given data:
pH of blood = 6.40
Hydrogen ion concentration = ?
Solution:
Formula:
pH = - log[H⁺]
by rearranging this formula,
[H⁺] = 10⁻(pH)
By putting values,
[H⁺] = 10 ⁻⁶°⁴⁰
[H⁺] = 3.98×10⁻⁷ M
Answer:
E) 0.0207
Explanation:
The molal concentration, m, is defined as the ratio between moles of solute (In this case, KBr) per kg of solvent (water):
<em>Moles KBr -Molar mass: 119g/mol-</em>
2.21g KBr * (1mol / 119g) = 0.01857moles
<em>Mass solvent:</em>
897g * (1kg / 1000g) = 0.897kg
Molal concentration:
0.01857 moles / 0.897kg =
0.0207m
Right solution is:
<h3>E) 0.0207.
</h3>
Answer:
Yes, there are forces of attraction between the surfaces.
It is adhesive force.
Explanation:
Adhesive force is the bonding between two or more molecules of different materials, causing them to stick together.
