Answer:
- A ball does not move unlesss you kick it and it rolls aways
- a car stays still and is not in motion, unless you start the engine
- a pencil stays still on a table, it moves when you pick it up off the table
Explanation:
Answer : Nuclear fusion plays an important role in making elements that are heavier than helium.
Explanation : In the given attachment it is clearly observed that nuclear fusion reactions are playing a vital role in making the small elements fuse together to form a higher element as a product. This is observed in those elements which are heavier than helium. The atoms of the elements fuse together and make a larger atomic molecule which is the sum of both the elemental masses.
Answer:
Approximately 4574.86 years
Explanation:
Hello,
To find the age of this sample, we should first of all convert the disintegration per minute to per year so that we can work on the same unit as our half life (T½), then we can find the disintegration constant and use it to find the year of the artifact.
Data;
T½ = 5730 years
Initial rate of radioactivity (No) = 15.3 disintegration per minute.
Current rate of radioactivity (N) = 8.8 disintegration per minute.
1 year = 525600 minutes
1 mins = 8.8 disintegration
525600mins = N disintegration
N = (525600 × 8.8) / 1
N = 4625280
1 mins = 15.3 disintegration
525600 mins = No
No = 8041680
But T½ = In2 / λ
λ = In2 / T½
λ = 0.693 / 5730
λ = 1.209×10⁻⁴ (this is the disintegration constant)
We can now find the how old the artifact is using our disintegration constant and other parameters.
In(N÷No) = -λt
In[4625280 / 8041680] = -(1.209×10⁻⁴ × t)
In[0.57516] = -1.209×10⁻⁴t
-0.5531 = -1.209×10⁻⁴ t
Solve for t
t = 0.5531 / 1.209×10⁻⁴
t = 4574.86 years
The artifact is approximately 4574.86 years
Answer:
The Ka is 9.11 *10^-8
Explanation:
<u>Step 1: </u>Data given
Moles of HX = 0.365
Volume of the solution = 835.0 mL = 0.835 L
pH of the solution = 3.70
<u>Step 2:</u> Calculate molarity of HX
Molarity HX = moles HX / volume solution
Molarity HX = 0.365 mol / 0.835 L
Molarity HX = 0.437 M
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<u>Step 3:</u> ICE-chart
[H+] = [H3O+] = 10^-3.70 = 1.995 *10^-4
Initial concentration of HX = 0.437 M
Initial concentration of X- and H3O+ = 0M
Since the mole ratio is 1:1; there will react x M
The concentration at the equilibrium is:
[HX] = (0.437 - x)M
[X-] = x M
[H3O+] = 1.995*10^-4 M
Since 0+x = 1.995*10^-4 ⇒ x=1.995*10^-4
[HX] = 0.437 - 1.995*10^-4 ≈ 0.437 M
[X-] = x = 1.995*10^-4 M
<u>Step 4: </u>Calculate Ka
Ka = [X-]*[H3O+] / [HX]
Ka = ((1.995*10^-4)²)/ 0.437
Ka = 9.11 *10^-8
The Ka is 9.11 *10^-8