Respuesta :
125 Each half life it divides by 2 the amount
1000/2=500
500/2=250
250/2=125
Answer : The atoms of Na-24 remaining are, 125.1 atoms
Explanation :
Half-life = 15 hours
First we have to calculate the rate constant, we use the formula :
[tex]k=\frac{0.693}{t_{1/2}}[/tex]
[tex]k=\frac{0.693}{15\text{ hours}}[/tex]
[tex]k=4.62\times 10^{-2}\text{ hours}^{-1}[/tex]
Now we have to calculate the left atoms of Na-24.
Expression for rate law for first order kinetics is given by:
[tex]t=\frac{2.303}{k}\log\frac{a}{a-x}[/tex]
where,
k = rate constant = [tex]4.62\times 10^{-2}\text{ hours}^{-1}[/tex]
t = time passed by the sample = 45 hours
a = initial atoms of the reactant = 1000
a - x = atoms left after decay process = ?
Now put all the given values in above equation, we get
[tex]45=\frac{2.303}{4.62\times 10^{-2}}\log\frac{1000}{a-x}[/tex]
[tex]a-x=125.1atoms[/tex]
Therefore, the atoms of Na-24 remaining are, 125.1 atoms
