Answer:
no. of moles = measured mass of substance/ molar mass of the constituted elements
Explanation:
No. of moles of 2.0g NaCl= 2/(23+35.5) = 0.034mol
There are three atoms in total! Hope this can help you out!
Answer:

Explanation:
Hello there!
In this case, according to the solubility equilibrium of calcium hydroxide:

Whereas the equilibrium expression is:
![Ksp=[Ca^{2+}][OH^-]^2](https://tex.z-dn.net/?f=Ksp%3D%5BCa%5E%7B2%2B%7D%5D%5BOH%5E-%5D%5E2)
It is firstly necessary to calculate the molar solubility given the grams and volume of the dissolved solute:

Now, according to the Ksp expression, we plug in s as the solubility to obtain:

Regards!
Answer:
0.43.
Explanation:
In order to solve this question we will need the an equation called Henderson-Hasselbalch Equation. The Henderson-Hasselbalch Equation can be represented by the reaction below;
pH= pKa + log ( [ A^- ] / [ HA] ).
Where HA is the acetic acid and A^- is the Acetate ion
We are given the pH value to be = 4.38 and the ka to be = 1.76×10^–5. So, we will use the value for the ka to find the pKa through the formula below.
pKa = - log ka.
Therefore, pKa = - log( 1.76×10^–5).
pKa= 4.75 + log
So,
4.38 = 4.75 + log ([ A^-] / [HA]).
4.38 - 4.75 = log ( [ A^- ] / [ HA] ).
( [ A^- ] / [ HA] ) = 10^- 0.37.
( [ A^- ] / [ HA] ) = 0.42657951880159265.
( [ A^- ] / [ HA] )= 0.43.