Answer:
t = 7.58 * 10¹⁹ seconds
Explanation:
First order rate constant is given as,
k = (2.303
/t) log [A₀]
/[Aₙ]
where [A₀] is the initial concentraion of the reactant; [Aₙ] is the concentration of the reactant at time, <em>t</em>
[A₀] = 615 calories;
[Aₙ] = 615 - 480 = 135 calories
k = 2.00 * 10⁻²⁰ sec⁻¹
substituting the values in the equation of the rate constant;
2.00 * 10⁻²⁰ sec⁻¹ = (2.303/t) log (615/135)
(2.00 * 10⁻²⁰ sec⁻¹) / log (615/135) = (2.303/t)
t = 2.303 / 3.037 * 10⁻²⁰
t = 7.58 * 10¹⁹ seconds
Answer:
4. Option C. Pentane.
5. Option D.
Explanation:
4. Hydrocarbons are compound containing carbon and hydrogen only. Hydrocarbons are said to be saturated when they contain only carbon to carbon single bond. All alkanes are saturated hydrocarbon.
The correct answer is pentane.
5. Isomerism is the phenomenon whereby two or more compounds have the same molecular formula but different structural patterns. The compounds involved are called isomers.
A careful observation of the diagram above shows that only option D satisfied the definition of Isomerism as the two compound both have the same molecular formula as C3H8O but different structural patterns.
Note: option C does not contain isomers as Isomerism can not occur in a compound having just 1 carbon atom.
<span>The roman numeral 3 represents the oxidation of the metal, scandium. </span>
The amount of the 240 g sample of the radioisotope that will remain after 525 billion years is 7.5 g
<h3>How to the number of half-lives that has elapsed</h3>
- Half-life (t½) = 105 billion years
- Time (t) = 525 billion years
- Number of half-lives (n) = ?
n = t / t½
n = 525 / 105
n = 5
<h3>How to determine the amount remaining</h3>
- Original amount (N₀) = 240 g
- Number of half-lives (n) = 5
- Amount remaining (N) = ?
N = N₀ / 2ⁿ
N = 240 / 2⁵
N = 240 / 32
N = 7.5 g
Learn more about half life:
brainly.com/question/26374513
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