A proton's mass is 1.6726231*10-27 kg, and the size of its radius is around 0.84×10−15 to 0.87×10−15 m.
Answer:
The amount of drug left in his body at 7:00 pm is 315.7 mg.
Explanation:
First, we need to find the amount of drug in the body at 90 min by using the exponential decay equation:

Where:
λ: is the decay constant = 
: is the half-life of the drug = 3.5 h
N(t): is the quantity of the drug at time t
N₀: is the initial quantity
After 90 min and before he takes the other 200 mg pill, we have:

Now, at 7:00 pm we have:

Therefore, the amount of drug left in his body at 7:00 pm is 315.7 mg (from an initial amount of 400 mg).
I hope it helps you!
Answer: Option (b) is the correct answer.
Explanation:
A covalent bond is defined as the bond which occurs due to sharing of electrons between the combining atoms.
Generally, a covalent bond is formed between non-metals.
For example, both nitrogen and oxygen atoms are non-metals and they combine covalently to form
compound.
As nitrogen has 5 valence electrons and an oxygen atom has 6 valence electrons. So, there occurs unequal sharing of electrons between the two.
Thus, we can conclude that when a covalent bond forms then electrons in valence shells are shared between atoms.
Answer: 1.
2. 3 moles of
: 2 moles of 
3. 0.33 moles of
: 0.92 moles of 
4.
is the limiting reagent and
is the excess reagent.
5. Theoretical yield of
is 29.3 g
Explanation:
To calculate the moles :

The balanced chemical equation is:
According to stoichiometry :
3 moles of
require = 2 moles of
Thus 0.33 moles of
will require=
of
Thus
is the limiting reagent as it limits the formation of product and
is the excess reagent.
As 3 moles of
give = 2 moles of
Thus 0.33 moles of
give =
of
Theoretical yield of
Thus 29.3 g of aluminium chloride is formed.
Answer:
Therefore, The indicator that is best fit for the given titration is Bromocresol Green Color change from pH between 4.0 to 5.6
Bromocresol green, color change from pH = 4.0 to 5.6
Explanation:
The equation for the reaction is :

concentration of
= 10%
10 g of
in 100 ml solution
molar mass = 45.08 g/mol
number of moles = 10 / 45.08
= 0.222 mol
Molarity of 
= 2.22 M
number of moles of
in 20 mL can be determined as:

Concentration of 
= 2.22 M
Similarly, The pKa Value of
is given as 10.75
pKb value will be: 14 - pKa
= 14 - 10.75
= 3.25
the pH value at equivalence point is,
![pH= \frac{1}{2}pKa - \frac{1}{2}pKb-\frac{1}{2}log[C]](https://tex.z-dn.net/?f=pH%3D%20%5Cfrac%7B1%7D%7B2%7DpKa%20-%20%5Cfrac%7B1%7D%7B2%7DpKb-%5Cfrac%7B1%7D%7B2%7Dlog%5BC%5D)
![pH = \frac{14}{2}-\frac{3.25}{2}-\frac{1}{2}log [2.22]](https://tex.z-dn.net/?f=pH%20%3D%20%5Cfrac%7B14%7D%7B2%7D-%5Cfrac%7B3.25%7D%7B2%7D-%5Cfrac%7B1%7D%7B2%7Dlog%20%5B2.22%5D)

Therefore, The indicator that is best fit for the given titration is Bromocresol Green Color change from pH between 4.0 to 5.6