Answer:
You must add 48.97 mL of water to make the 0.200 M diluted solution.
Explanation:
In chemistry, dilution is the reduction in concentration of a chemical in a solution. In other words, it is the process of reducing the concentration of solute in solution, simply adding more solvent to the solution.
In a dilution, the quantity or mass of the solute is not changed but only that of the solvent. As only solvent is being added, by not increasing the amount of solute the concentration of the solute decreases.
The expression for the dilution calculations is:
Cinitial* Vinitial = Cfinal* Vfinal
In this case:
- Cinitial= 12 M
- Vinitial= 0.830 mL
- Cfinal= 0.200 M
- Vfinal= ?
Replacing:
12 M*0.830 mL= 0.200 M*Vfinal
Solving:
Vfinal= 49.8 mL
Since 0.830 mL is the volume you initially have of HCl, the amount of water you must add is:
49.8 mL - 0.830 mL= 48.97 mL
<u><em>You must add 48.97 mL of water to make the 0.200 M diluted solution.</em></u>
Atomic mass Boron ( B ) = 10.811 u.m.a
10.811 g -------------- 6.02x10²³ atoms
5.40 g ----------------- ?? atoms
5.40 x ( 6.02x10²³) / 10.811 =
3.0069x10²³ atoms
Answer:
![\frac{[F^{-}]}{[HF]}](https://tex.z-dn.net/?f=%5Cfrac%7B%5BF%5E%7B-%7D%5D%7D%7B%5BHF%5D%7D)
is larger
Explanation:
, where 
is the acid dissociation constant.
For a monoprotic acid e.g. HA, ![K_{a}=\frac{[H^{+}][A^{-}]}{[HA]}](https://tex.z-dn.net/?f=K_%7Ba%7D%3D%5Cfrac%7B%5BH%5E%7B%2B%7D%5D%5BA%5E%7B-%7D%5D%7D%7B%5BHA%5D%7D)
and ![\frac{[A^{-}]}{[HA]}=\frac{K_{a}}{[H^{+}]}](https://tex.z-dn.net/?f=%5Cfrac%7B%5BA%5E%7B-%7D%5D%7D%7B%5BHA%5D%7D%3D%5Cfrac%7BK_%7Ba%7D%7D%7B%5BH%5E%7B%2B%7D%5D%7D)
So, clearly, higher the value , lower will the the 
In this mixture, at equilibrium, ![[H^{+}]](https://tex.z-dn.net/?f=%5BH%5E%7B%2B%7D%5D)
will be constant.
of HF is grater than of HCN
Hence, ![(\frac{F^{-}}{[HF]}=\frac{K_{a}(HF)}{[H^{+}]})>(\frac{CN^{-}}{[HCN]}=\frac{K_{a}(HCN)}{[H^{+}]})](https://tex.z-dn.net/?f=%28%5Cfrac%7BF%5E%7B-%7D%7D%7B%5BHF%5D%7D%3D%5Cfrac%7BK_%7Ba%7D%28HF%29%7D%7B%5BH%5E%7B%2B%7D%5D%7D%29%3E%28%5Cfrac%7BCN%5E%7B-%7D%7D%7B%5BHCN%5D%7D%3D%5Cfrac%7BK_%7Ba%7D%28HCN%29%7D%7B%5BH%5E%7B%2B%7D%5D%7D%29)
So, is larger
Answer:
SeF4 is a polar molecule
Explanation:
SeF4 is a polar molecule because a polar molecule is any molecule that have lone pairs of electrons in the central atom or have atoms that are electronegative and the electrons between that are covalently bonded are not evenly distributed.
The electronegative atoms of flourine in SeF4 are not evenly distributed and kind pairs of electrons are on the central atom.
Answer:
Tetrahedral, trigonal pyramidal, trigonal bipyramidal.
Explanation:
The VSPER theory states that the bonds of sharing electrons and the lone pairs of electrons will repulse as much as possible. So, by the repulsion, the molecule will have some shape.
In the ion PO₄³⁻, the central atom P has 5 electrons in its valence shell, so it needs 3 electrons to be stable. Oxygen has 6 electrons at the valence shell and needs 2 to be stable. 3 oxygens share 1 pair of electrons with P, and the two lone pair remaining in P is shared with the other O, then the central atom makes 4 bonds and has no lone pairs, the shape is tetrahedral.
In the ion H₃O⁺, the central atom O has 6 electrons in its valence shell and needs 2 electrons to be stable. The hydrogen has 1 electron, and need 1 more to be stable. The hydrogens share 1 pair of electrons with the oxygen, then it remains 3 electrons at the central atom, and the VSPER theory states that the shape will be a trigonal pyramidal.
In the AsF₅, the central atom As has 5 valence electrons, and F has 1 electron in its valence shell, so each F shares one pair of electrons with As, and there are no lone pairs in the central atom. For 5 bonds without lone pairs, the shape is trigonal bipyramidal.
