Answer:
I don't know..but plz follow me
Answer: B yeah I'm pretty sure
Answer:
Explanation:
count given by old sample = .97 disintegrations per minute per gram
count given by fresh sample = 6.68 disintegrations per minute per gram
Half life of radioactive carbon = 5568 years
rate of disintegration
dN / dt = λ N
In other words rate of disintegration is proportional to no of radioactive atoms present . As number reduces rate also reduces .
Let initial no of radioactive be N₀ and after time t , number reduces to N
N₀ / N = 6.68 / .97
Now



λ is disintegration constant
λ = .693 / half life
= .693 / 5568
= .00012446 year⁻¹
Putting the values in the equation above


1.929577 = .00012446 t
t = 15503.6 years .
<h3>
Answer:</h3>
0.643 moles
<h3>
Explanation:</h3>
We are given;
Density of nitrogen gas as 1.20 g/L
Volume nitrogen as 15.0 L
We are required to calculate the number moles of nitrogen gas;
<h3>Step 1: Determine the mass of nitrogen gas</h3>
We know the density is given by dividing mass by volume.
Therefore, to get the mass;
- Mass = Density × volume
- Mass = 1.20 g/L × 15.0 L
= 18 g
<h3>Step 2: Determine the mass of nitrogen gas </h3>
We know that to get the number of moles, we divide mass by molar mass;
That is, moles = Mass ÷ Molar mass
But, molar mass of nitrogen gas is 28 g/mol
Therefore;
Moles of nitrogen gas = 18 g ÷ 28 g/mol
= 0.643 moles
Therefore, the number of moles of nitrogen gas 0.643 moles