SI unit of frequency is Hertz(Hz)
Answer : Yes, a precipitate form when a solution of calcium chloride and a solution of mercury(I) nitrate are mixed together.
The net ionic equation will be,

Explanation :
In the net ionic equations, we are not include the spectator ions in the equations.
Spectator ions : The ions present on reactant and product side which do not participate in a reactions. The same ions present on both the sides.
The given balanced ionic equation will be,

The ionic equation in separated aqueous solution will be,

In this equation,
are the spectator ions.
By removing the spectator ions from the balanced ionic equation, we get the net ionic equation.
The net ionic equation will be,

Answer:
Potassium (K) has 19 protons.
Each neutral atom of Potassium has 19 electrons.
Explanation:
A) Potassium has 19 protons because the atomic number tells us how many protons are in an atom of the element. (The atomic number is the number above the element symbol. For example, the number above "K" is 19, which is the atomic number).
B) If an atom is neutral, this means that the atom has neutral energy. Protons give positive energy and electrons give negative energy. For the atom to be neutral, the atom must have balanced energy, therefore, making the number of electrons equal to the number of protons in a neutral atom.
Answer:
0.7atm
Explanation:
3.5/5 because constant temperature