I believe the correct answer from the choices listed above is the third option. It is amino acid that is not an example of a polymer. It <span> is a large molecule, or macromolecule, composed of many repeated subunits. Hope this answers the question.</span>
Answer:
Scientists know that today the Earth's magnetic field is powered by the solidification of the planet's liquid iron core. The cooling and crystallization of the core stirs up the surrounding liquid iron, creating powerful electric currents that generate a magnetic field stretching far out into space.
Barium carbonate (BaCO₃) <span>will be more soluble in acidic solution than in pure water, because Ksp (solubility constant) in water for this salt is very low.
In acid (for example hydrochloric acid) barium carbonate dissolves more because it forms weak electrolyte carbonic acid:
BaCO</span>₃(s) + 2HCl(aq) → BaCl₂(aq) + H₂CO₃(aq).
Volcanic eruptions are caused by earth's internal heat sources.
All the other choices are atmospheric or external earth.
Answer: The half-life of a first-order reaction is, 
Explanation:
All the radioactive reactions follows first order kinetics.
Rate law expression for first order kinetics is given by the equation:
![k=\frac{2.303}{t}\log\frac{[A_o]}{[A]}](https://tex.z-dn.net/?f=k%3D%5Cfrac%7B2.303%7D%7Bt%7D%5Clog%5Cfrac%7B%5BA_o%5D%7D%7B%5BA%5D%7D)
where,
k = rate constant = ?
t = time taken = 440 s
![[A_o]](https://tex.z-dn.net/?f=%5BA_o%5D)
= initial amount of the reactant = 0.50 M
[A] = left amount = 0.20 M
Putting values in above equation, we get:
The equation used to calculate half life for first order kinetics:
Putting values in this equation, we get:
Therefore, the half-life of a first-order reaction is,
