The translation of the question is
Commercial solutions of HCl (MP = 36.5 g / mol) are typically 39.0% W / W of this acid in water. Determine the molality of the HCl solution if its density is equal to 1.20 g / ml.
Answer:
Molality is 17.51 molal
Explanation:
We are given 39% w/w of HCl, this means for every 100g of this solution we have 39g of HCl in it.
to ease the calculation we assume we have 1L(1000ml) of this solution is present.
Density = mass /volume
1.20 = mass/1000
mass = 1200 g of solution
and we are given that 39% of this solution is will contain HCl
so
1200 * 39/100 = 468g of HCl present
no of moles of HCl = 468/36.5 = 12.82moles
mass of solution = mass of water + mass of acid
mass of water = mass of solution - mass of acid
Mass of water = 1200 - 468 = 732g of water
Molality = moles /masss of water in kg
= 12.82 *1000/732 =17.51molal
Answer is: D. The I⁻ ion and the positive end of a water molecule.
Dissociation of potassium iodide in water:
KI(aq) → K⁺(aq) + I⁻(aq).
Solvation is the interaction of solvent (water) with molecules or ions (in this example K⁺ and I⁻) in a solute.
Anion I⁻ has negative charge, so positive end (hydrogen atoms) of a water molecul attracts them.
Solvent (usually a liquid, but can also be a solid or a gas) is a substance that dissolves a solute.
Initial [ HCO2H] = moles * volume
=0.35 moles * 1 L = 0.35 M
by using ICE table:
HCO2H ↔ H+ + HCO2-
initial 0.35 M 0 0
change - X +X +X
Equ (0.35 - X) X X
∴ Ka = [H+][HCO2-] / [HCO2H]
by substitution:
1.8 x 10^-4 = X^2 / (0.35-X) by solving for X
∴ X = 0.0079 or 7.9 x 10^-3
∴ [H+] = X = 7.9 x 10^-3 M
Answer:
d. 10
Explanation:
The 24 means the atomic mass and twelve means the number of electrons. You subtract the number of electrons from the atomic mass. 24-12=12
Then, since there's +2, you subtract 2 from 12 which equals 10 which means there are 10 electrons now.
The confusing thing is that + means subtract and - means add here.
Hope this helps.
Because C-12 is fixed value of any organisms but the value of C-14 is constantly decreasing by time thats why every organism have their specific ratio of C14/C12
