Answer:
Explanation:
This question seeks to test the knowledge of separation techniques.
From the narration in the question, the first separation to be done is the removal of Iron fillings by the use of magnet (magnetic separation). Since Iron is magnetic, the iron fillings will be attracted by the magnet hence removing the iron fillings from the mixture.
The second constituent to be removed will be the copper pieces by the use of a sieve (sieving). Copper pieces have relatively larger sizes than sand and common salt, hence a sieve (which separates particles based on size) can be used to remove the copper pieces from the mixture.
What will be left in the mixture after the processes above will be salt and water. This mixture will have to be dissolved in water; the salt will dissolve in water while the sand will not. After which, filtration will be done to remove the sand which will be collected on the filter paper as filtride and the salt solution will pass through the filter paper as filtrate.
The salt solution can then be evaporated to dryness to retrieve the solid salt from the solution.
The amount of salt in the mixture can then be measured using a weighing balance.
Some of safety measures to be taken during the course of this experiment includes performing the experiment in an airtight and controlled environment. Lab coat and hand gloves should be worn during the course of the experiment. The evaporation to dryness should not be done close to an inflammable material/substance
Answer:
The expression for the number of moles is 5.0 g / 56 g/mol
Explanation:
The mole is the amount of substance that contains as many entities as there are carbon atoms in 12 grams of a carbon-12 isotope. It is the amount of a substance that contains the same number of units as the number of atoms in 12g of carbon - 12 isotope. A mole of an ionic substance contains 6.02 * 10^23 atoms of the element. Mathematically, moles is the mass of a substance in grams divided by the relative molecular mass.
Moles = mass / relative molecular mass
In the given question, mass = 5.0 g
Molecular mass of CaO ( Ca= 40, O = 16) = ( 40 + 16) g/mol = 56 g/mol
Moles = 5.0 g/ 56 g/mol is the expression for the number of moles in 5.0 g of CaO
Answer:
Acid :
Conjugate base :
Base:
Explanation:
According to the Lewis concept :
- An acid is defined as a substance that accepts electron pairs .
- Base is defined as a substance which donates electron pairs.
According to the Bronsted-Lowry conjugate acid-base theory:
- An acid is defined as a substance which looses donates protons and thus forming conjugate base .
- A base is defined as a substance which accepts protons and thus forming conjugate acid.
Given reaction :
is acting as an acid because it is accepting hydroxide ion.And after accepting hydroxide ion it forms its conjugate base that is
Since, is acting as an acid will obviously act as base.
Answer:
Explanation:
Step 1: Data given
The equilibrium constant, Kc, for the following reaction is 4.76 * 10^-4 at 431 K
The equilibrium concentration of Cl2(g) is 0.233 M
Step 2: The balanced equation
PCl5(g) ⇄ PCl3(g) + Cl2(g)
Step 3: The initial concentration
[PCl5]= Y M
[PCl] = 0M
[Cl2] = 0M
Step 4: Calculate the concentration at equilibrium
[PCl5] = Y + X M = Y - 0.233 M
[PCl]= XM = 0.233 M
[Cl2]= XM = 0.233 M
Step 5: Define Kc
Kc = [Cl2]* [PCl3] / [PCl5]
4.76 * 10^-4 = 0.233² / (Y -0.233)
0.000476 = 0.05429 / (Y - 0.233)
Y - 0.233 = 0.05429 / 0.000476
Y - 0.233 = 114.05 M
Y = 114.283 M = the initial concentration
The concentration of PCl5 at the equilibrium is 114.05 M