Answer:
3,964 years.
Explanation:
- It is known that the decay of a radioactive isotope isotope obeys first order kinetics.
- Half-life time is the time needed for the reactants to be in its half concentration.
- If reactant has initial concentration [A₀], after half-life time its concentration will be ([A₀]/2).
- Also, it is clear that in first order decay the half-life time is independent of the initial concentration.
- The half-life of the element is 5,730 years.
- For, first order reactions:
<em>k = ln(2)/(t1/2) = 0.693/(t1/2).</em>
Where, k is the rate constant of the reaction.
t1/2 is the half-life of the reaction.
∴ k =0.693/(t1/2) = 0.693/(5,730 years) = 1.21 x 10⁻⁴ year⁻¹.
- Also, we have the integral law of first order reaction:
<em>kt = ln([A₀]/[A]),</em>
where, k is the rate constant of the reaction (k = 1.21 x 10⁻⁴ year⁻¹).
t is the time of the reaction (t = ??? year).
[A₀] is the initial concentration of the sample ([A₀] = 100%).
[A] is the remaining concentration of the sample ([A] = 61.9%).
∴ t = (1/k) ln([A₀]/[A]) = (1/1.21 x 10⁻⁴ year⁻¹) ln(100%/61.9%) = 3,964 years.
Answer:
B) irreversible process
Explanation:
The process given here is irreversible.
The kind of reaction that occurs when you mix aqueous solutions of barium sulfide and sulfuric acid is a precipitation reaction.
<h3>Further Explanation</h3>
- The chemical reaction between Ba(OH)2(aq) and H2SO4(aq) is given by;
Ba(OH)₂(aq) + H₂SO4(aq) --> BaSO₄(aq) + 2H₂O(l)
- This is a type of precipitation reaction, where a precipitate is formed after the reaction, that is Barium sulfate.
<h3>Other types of reaction</h3><h3>Neutralization reactions </h3>
- These are reactions that involve reacting acids and bases or alkali to form salt and water as the only products.
- For example a reaction between sodium hydroxide and sulfuric acid.
NaOH(aq) + H₂SO₄(aq) → Na₂SO₄(aq) + H₂O(l)
<h3>Displacement reactions</h3>
- These are reactions in which a more reactive atom or ion displaces a less reactive ion from its salt.
Mg(s) + CuSO₄(aq) → MgSO₄(aq) + Cu(s)
<h3>Redox reactions </h3>
- These are reactions that involve both reduction and oxidation occuring simultaneously durin a chemical reaction.
- For example,
Mg(s) + CuSO₄(aq) → MgSO₄(aq) + Cu(s)
- Magnesium atom undergoes oxidation while copper ions undergoes reduction.
<h3>Decomposition reactions</h3>
- These are type of reactions that involves breakdown of a compound into its constituents elements.
- For example decomposition of lead nitrate.
Pb(NO3)2(S) → PbO(s) + O2(g) + NO2(g)
Keywords: Precipitation
<h3>Learn more about: </h3>
Level: High school
Subject: Chemistry
Topic: Chemical reactions
Sub-topic: Precipitation reactions
The answer is b (bladder)
Add an alkaline compound to raise the pH to 7.2.
