12.5% of strontium-90 would remain in a sample after three half-lives have passed. Half-life automatically means 50% of the original amount would remain.
Answer:
50 mL
Explanation:
We can solve this problem by using Boyle's Law, which states that:
"For a fixed mass of an ideal gas kept at constant temperature, the pressure of the gas is inversely proportional to its volume"
Mathematically:

where
p is the pressure of the gas
V is the volume of the gas
The equation can be rewritten as

where in this problem:
is the initial pressure of the gas in the coke
is the initial volume
is the final pressure
Solving for V2, we find the final volume:

<span>The representative particle for silicon is atom of silicon.
</span>Representative particles can be atoms, molecules, formula units or ions. Representative particles depend on the nature of the substance. Silicon is chemical element made of atoms.
For sodium chloride (NaCl) for example, representative particles are ions.
Answer:
a) E2
b) SN2
c) SN2
Explanation:
A substitution reaction involves replacement of an atom or group in a molecule by another atom or group. An elimination reaction is the loss of two atoms from the same molecule leading to the formation of a multiple bond in the molecule.
We must note that primary alkyl halides never undergo SN1/E1 reactions. However, the presence of a strong bulky base such as tert BuO- , E2 reactions predominate. In the presence of strong bases such as OH^- and good nucleophiles such as I^-, SN2 mechanism predominates.