Answer: You know that monomers that are joined by condensation polymerization have two functional groups. You also know (from Part 6) that a carboxylic acid and an amine can form an amide linkage, jand a carboxylic acid and an alcohol can form an ester linkage.
<u>Given:</u>
Mass of Ag = 1.67 g
Mass of Cl = 2.21 g
Heat evolved = 1.96 kJ
<u>To determine:</u>
The enthalpy of formation of AgCl(s)
<u>Explanation:</u>
The reaction is:
2Ag(s) + Cl2(g) → 2AgCl(s)
Calculate the moles of Ag and Cl from the given masses
Atomic mass of Ag = 108 g/mol
# moles of Ag = 1.67/108 = 0.0155 moles
Atomic mass of Cl = 35 g/mol
# moles of Cl = 2.21/35 = 0.0631 moles
Since moles of Ag << moles of Cl, silver is the limiting reagent.
Based on reaction stoichiometry: # moles of AgCl formed = 0.0155 moles
Enthalpy of formation of AgCl = 1.96 kJ/0.0155 moles = 126.5 kJ/mol
Ans: Formation enthalpy = 126.5 kJ/mol
Answer:
Here's what I get
Explanation:
A plant extract is a mixture because it contains different substances: acetone or ethanol, chlorophylls A and B, carotene and xanthophylls.
It is homogeneous because it is a solution. There is only one phase: the liquid phase. You cannot see the pigments as separate phases.
You can separate the pigments by paper, thin layer, or column chromatography.
Many schools use paper chromatography, because paper is cheap.
As the mixture of pigments follows the solvent up the paper, they separate into different coloured bands according to their attractive forces to the cellulose in the paper.
The chlorophylls are strongly attracted to the paper, so they don't travel very far.
The nonpolar carotene molecules have little attraction to the polar cellulose, so they are carried along by the solvent front.
Answer:
valence electrons are necessary for an atom to reach a state of stability.
Explanation:
A 0.25m solution of NaCl is defined as a solution consisting of 0.25mol NaCl dissolved in 1kg water:
Which choice fits this definition: None does. I suggest that you recheck the data you have submitted - you have a mixture of moles, mass, etc and it is easy to make a mistake.
d) looks promising if it was: 1.0 mol NaCl dissolved in 4kg water.
I have overlooked C) as possible 0.25mol NaCl in 1kg water as being a little too obvious.
