we have,
wavelenght=c/f
where c= 3×10^8 m/s
f=6.3×10^12 s^-1
so wavelength=(3×10^8)/(6.3×10^12)
=0.476×10^-4 m
I found these four statements for that question:
Each molecule contains four different elements.
Each molecule contains three atoms.
Each molecule contains seven different bonds.
Each molecule contains six oxygen atoms.
The last one is true. Each molecule contains six oxygen atoms.
The number to the right of O and of (NO3) ares subscripts.
The chemical formula uses subscripts to indicate the number of atoms.
The subscript 2 in (NO3)2 means that there are two NO3 radicals.
And the subscript 3 to the right of O means that each NO3 radical has three atoms of O.
Then, the number of atoms of O is 2 * 3 = 6.
So, the true statement is the last one: each molecule of Ba (NO3)2 has six atoms of O.
From that molecule you can also tell:
- Each molecule contains one atom of barium
- Each molecule contains two atoms of nitrogen
- Each molecule contains two NO3 radicals
To minimize the sharp pH shift that occurs when a strong acid is added to a solution, IT IS PRACTICAL TO ADD A WEAK BASE.
When a strong acid is added to a solution, it usually brings about a sharp change in the pH of the concerned solution. To avoid this, one can add a weak base to the solution first. The weak base will serves as a buffer for the strong acid and prevents the solution from experiencing sharp pH variations.
