Answer:
A
Explanation:
A. The pencil is on the table in broad daylight
Try to have a calm morning before camp. A good night’s sleep and a good breakfast. Make sure to be cautious, follow all the rules for certain areas ( some maybe restricted ). Take lots of photos doing wacky stuff! Learn but have fun learning
Answer;
The above statement is false
Explanation;
Symmetrical distribution, commonly known as symmetric distribution or normal distribution, is typically unimodal, meaning it shows only one peak in graph form.
It is a type of distribution where the left side of the distribution mirrors the right side. By definition, a symmetric distribution is never a skewed distribution.
All normal distributions are symmetric and have bell-shaped density curves with a single peak.
That is true Step by step:
Answer : The time passed in years is 20.7 years.
Explanation :
Half-life = 28.1 years
First we have to calculate the rate constant, we use the formula :
![k=\frac{0.693}{t_{1/2}}](https://tex.z-dn.net/?f=k%3D%5Cfrac%7B0.693%7D%7Bt_%7B1%2F2%7D%7D)
![k=\frac{0.693}{28.1\text{ years}}](https://tex.z-dn.net/?f=k%3D%5Cfrac%7B0.693%7D%7B28.1%5Ctext%7B%20years%7D%7D)
![k=2.47\times 10^{-2}\text{ years}^{-1}](https://tex.z-dn.net/?f=k%3D2.47%5Ctimes%2010%5E%7B-2%7D%5Ctext%7B%20years%7D%5E%7B-1%7D)
Now we have to calculate the time passed.
Expression for rate law for first order kinetics is given by:
![t=\frac{2.303}{k}\log\frac{a}{a-x}](https://tex.z-dn.net/?f=t%3D%5Cfrac%7B2.303%7D%7Bk%7D%5Clog%5Cfrac%7Ba%7D%7Ba-x%7D)
where,
k = rate constant = ![2.47\times 10^{-2}\text{ years}^{-1}](https://tex.z-dn.net/?f=2.47%5Ctimes%2010%5E%7B-2%7D%5Ctext%7B%20years%7D%5E%7B-1%7D)
t = time passed by the sample = ?
a = initial amount of the reactant = 1.00 g
a - x = amount left after decay process = 0.600 g
Now put all the given values in above equation, we get
![t=\frac{2.303}{2.47\times 10^{-2}}\log\frac{1.00}{0.600}](https://tex.z-dn.net/?f=t%3D%5Cfrac%7B2.303%7D%7B2.47%5Ctimes%2010%5E%7B-2%7D%7D%5Clog%5Cfrac%7B1.00%7D%7B0.600%7D)
![t=20.7\text{ years}](https://tex.z-dn.net/?f=t%3D20.7%5Ctext%7B%20years%7D)
Therefore, the time passed in years is 20.7 years.