When we have:
Zn(OH)2 → Zn2+ 2OH- with Ksp = 3 x 10 ^-16
and:
Zn2+ + 4OH- → Zn(OH)4 2- with Kf = 2 x 10^15
by mixing those equations together:
Zn(OH)2 + 2OH- → Zn(OH)4 2- with K = Kf *Ksp = 3 x 10^-16 * 2x10^15 =0.6
by using ICE table:
Zn(OH)2 + 2OH- → Zn(OH)4 2-
initial 2m 0
change -2X +X
Equ 2-2X X
when we assume that the solubility is X
and when K = [Zn(OH)4 2-] / [OH-]^2
0.6 = X / (2-2X)^2 by solving this equation for X
∴ X = 0.53 m
∴ the solubility of Zn(OH)2 = 0.53 M
Answer:
B. Chemical changes produce new substances; physical changes do not.
Explanation:
Physical changes only alter appearances, while chemical changes are interactions that create new chemical formulas.
B is gas
The chemical element krypton is classed as a noble gas and a nonmetal.
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First, find out how many grams are in one mole of CO2(the two oxygen atoms means you need to multiply oxygen’s amu by 2,then add whatever carbon’s amu is to that). Then divide 26 grams by that number and that will be your moles. There are only two significant figures, so round your answer correctly.
Answer:
1.263 moles of HF
Explanation:
The balance chemical equation for given single replacement reaction is;
Sn + 2 HF → SnF₂ + H₂
Step 1: <u>Calculate Moles of Tin as;</u>
As we know,
Moles = Mass / A.Mass ----- (1)
Where;
Mass of Tin = 75.0 g
A.Mass of Tin = 118.71 g/mol
Putting values in eq. 1;
Moles = 75.0 g / 118.71 g/mol
Moles = 0.6318 moles of Sn
Step 2: <u>Find out moles of Hydrogen Fluoride as;</u>
According to balance chemical equation,
1 mole of Sn reacted with = 2 moles of HF
So,
0.6318 moles of Sn will react with = X moles of HF
Solving for X,
X = 0.6318 mol × 2 mol / 1 mol
X = 1.263 moles of HF
