Answer:
6.73g
Explanation:
T½ = 5.2days
No = 80g
N = ?
T = 20.8days
We'll have to find the disintegration constant first so that we can plug it into the equation that will help us find the mass of the sample after 20.8 days
T½ = In2 / λ
T½ = half life
λ = disintegration constant
λ = In2 / T½
λ = 0.693 / 5.8
λ = 0.119
In(N / No) = -λt
N = final mass of the radioactive sample
No = initial mass of the sample
λ = disintegration constant
t = time for the radioactive decay
In(N/No) = -λt
N / No = e^-λt
N = No(e^-λt)
N = 80 × e^-(0.119 × 20.8)
N = 80 × e^-2.4752
N = 80 × 0.0841
N = 6.728g
The mass of the sample after 20.8 days is approximately 6.73g
D. Sodium and Chlorine
Sodium has 1 electron and Chlorine has 7 electrons. For a compound to be stable, they must have 8 electrons. NaCl = 8 electrons
Fun Fact- You eat NaCl everyday. It's table salt which you put in food.
First we will calculate the number of moles of Iron:
, where n is the number of moles, m is the mass of iron in the reaction and M is the Atomic weight.
moles of Iron.
The same number of moles of Oxygen will take part in the reaction.
So
where 32 is the Atomical Weight of Oxygen (16 x 2).
=>
g
Answer:
the sample undergo 
disintegrations per second.
Explanation:
Given:
The amount of sulphur purchased is 0.671 μCi
To find:
disintegrations per second = ?
Solution:
Some of the conversions are
1 rad = 0.01 Gy
1Gy = 1 j/kg tissue
1 rem = 0.01 Sv
1Sv = 1 j/Kg
Using these conversions,
The decay rate of this sample is calculated as
= disintegrations per second
Answer:
18.2 g.
Explanation:
You need to first figure out how many moles of nitrogen gas and hydrogen (gas) you have. To do this, use the molar masses of nitrogen gas and hydrogen (gas) on the periodic table. You get the following:
0.535 g. N2 and 1.984 g. H2
Then find out which reactant is the limiting one. In this case, it's N2. The amount of ammonia, then, that would be produced is 2 times the amount of moles of N2. This gives you 1.07 mol, approximately. Then multiply this by the molar mass of ammonia to find your answer of 18.2 g.
