Answer:
Option (A)
Explanation:
Radioactivity is defined as a process in which an unstable atomic nucleus decays continuously and after a specific period of time changes into a much more stable element. During this time of decay, the nucleus emits charged particles (energy) which are known as the α, β and γ particles. These are often emitted in the form of electromagnetic energy and are very dangerous to health.
The radioactive elements decay at a certain rate which is commonly known as the half-life. Half-life is basically defined as the time required by a radioactive substance to decay half of its initial composition.
Thus, the correct answer is option (A).
Atomic mass Ca = 40 a.m.u
1 mole Ca ----------- 40 g
2.5 mols Ca -------- ( mass Ca )
Mass Ca = 2.5 x 40 / 1
Mass Ca = 100 / 1
= 100 g of Ca
hope this helps!
Answer:
Only the number of neutrons change.
Answer:
0.0126 moles are released
Explanation:
Using Henry's law, where the amount of dissolved gas in a liquid is proportional to its partial pressure above the liquid:
S = k×P
<em>Where S is solubility (5.6x10⁻⁴molL⁻¹), k is Henry's constant and P is partial pressure (0.80atm)</em>
Replacing:
<em>5.6x10⁻⁴molL⁻¹ / 0.80atm = 7x10⁻⁴molL⁻¹atm⁻¹</em>
Thus, with Henry's constant, solubility of N₂ when partial pressure is 3.8atm is:
S = 7x10⁻⁴molL⁻¹atm⁻¹ × 3.8atm
S = 2.66x10⁻³molL⁻¹
Thus, when the deepd-sea diver has a pressure of 3.8amt, moles dissolved are:
6.0L × 2.66x10⁻³molL⁻¹ = <em>0.01596 moles of N₂</em>
At the surface, pressure is 0.80atm and solubility is 5.6x10⁻⁴molL⁻¹, moles dissolved are:
6.0L × 5.6x10⁻⁴molL⁻¹ = <em>3.36x10⁻³mol</em>
Thus, released moles are:
0.01596mol - 3.36x10⁻³mol = <em>0.0126 moles are released</em>
The half-life in months of a radioactive element that reduce to 5.00% of its initial mass in 500.0 years is approximately 1389 months
To solve this question, we'll begin by calculating the number of half-lives that has elapsed. This can be obtained as follow:
Amount remaining (N) = 5%
Original amount (N₀) = 100%
<h3>Number of half-lives (n) =?</h3>
N₀ × 2ⁿ = N
5 × 2ⁿ = 100
2ⁿ = 100/5
2ⁿ = 20
Take the log of both side
Log 2ⁿ = log 20
nlog 2 = log 20
Divide both side by log 2
n = log 20 / log 2
<h3>n = 4.32</h3>
Thus, 4.32 half-lives gas elapsed.
Finally, we shall determine the half-life of the element. This can be obtained as follow.
Number of half-lives (n) = 4.32
Time (t) = 500 years
<h3>Half-life (t½) =? </h3>
t½ = t / n
t½ = 500 / 4.32
t½ = 115.74 years
Multiply by 12 to express in months
t½ = 115.74 × 12
<h3>t½ ≈ 1389 months </h3>
Therefore, the half-life of the radioactive element in months is approximately 1389 months
Learn more: brainly.com/question/24868345
