Answer:
The mass fraction of ferric oxide in the original sample :
Explanation:
Mass of the mixture = 3.110 g
Mass of 
Mass of 
After heating the mixture it allowed to react with hydrogen gas in which all the ferric oxide reacted to form metallic iron and water vapors where as aluminum oxide did not react.
Mass of mixture left after all the ferric oxide has reacted = 2.387 g
Mass of mixture left after all the ferric oxide has reacted = y
The mass fraction of ferric oxide in the original sample :
Answer:
pH ≅ 4.80
Explanation:
Given that:
the volume of HN₃ = 25 mL = 0.025 L
Molarity of HN₃ = 0.150 M
number of moles of HN₃ = 0.025 × 0.150
number of moles of HN₃ = 0.00375 mol
Molarity of NaOH = 0.150 M
the volume of NaOH = 13.3 mL = 0.0133
number of moles of NaOH = 0.0133× 0.150
number of moles of NaOH = 0.001995 mol
The chemical equation for the reaction of this process can be written as:
1 mole of hydrazoic acid react with 1 mole of hydroxide to give nitride ion and water
thus the new number of moles of HN₃ = 0.00375 - 0.001995 = 0.001755 mol
Total volume used in the reaction = 0.025 + 0.0133 = 0.0383 L
Concentration of 
= 
= 0.0458 M
Concentration of 
= 
= 0.0521 M
GIven that :
Ka = 
Thus; it's pKa = 4.72
pH ≅ 4.80
Potassium hypochlorite when dissolved in water would dissociate into ions namely the potassium ions and the hypochlorite ions. Furthermore, hypochlorite ions would interact with water molecules and would decompose further. The dissociation reactions are as follows:
KClO <=> K+ + ClO-
ClO- + H2O <=> HOCl + OH-
Adding the two reactions, would give
KClO + ClO- + H2O = K+ + HOCl + OH- + ClO-
The two ClO- ions in both sides would cancel giving us the net ionic equation:
KClO + H2O = K+ + HOCl + OH-
The overall molecule is Polar because the shape of the molecule is Trigonal Pyramidal, which means it has the lone pair electrons. Becuase of the lone pair the pulling is unequal.
H3O+ has 3 polar bonds.
To know if the bonds are polar or nonpolar find the difference of the element's electronegativity charge.
H has electronegativity charge of 2.2, and O has 3.4.
Always subtract the smaller number from the greater one.
So 3.4 - 2.2 = 1.2
If the difference is from 0-0.4 the bond is nonpolar, but if it's from 0.5-1.9 the bond is polar.
So, 1.2 is polar bond. So H3O+ has 3 polar bonds, and the overall molecule is polar too.
A simple way to know if it's polar or nonpolar is to draw the lewis dot structure, and use VSEPR.
A volumetric flask is used to contain a predetermined volume of substance and only measures that volume, for example 250 ml.
Conical flasks can be used to measure the volume of substances but the accuracy they provide is usually up to 10ml. Conical flasks are used in titrations, reactions where the liquid may boil, and reactions which involve stirring.
Pippettes are of two types, volumetric and graduated. Pippettes are used where high accuracy is required and volumetric pippettes come in as little as 1 ml. Pippettes are usually used in titrations.
Graduated cylinders come in a wide variety of sizes and their accuracy can be down to as much as 1 ml. They are used to contain liquids.
