Atomic Structure And Bonding
Name the shape of Carbon Dioxide molecule.
Linear
State Avorgado's constant.
6.02 x 1023
State two uses of Chlorine gas.
Green-yellowish, Pungent smell, denser than air.
Bleaching, manufacture of HCl, disinfectant in swimming pools.
Name an unsaturated hydrocarbon and draw its structural formula.
Alkene, Alkyne
Ethene, Ethyne
Name the following molecule:
K2Cr2O7
KMnO4
Potassium Dichromate
Potassium Permanganate.
Write the electron configuration for O2-
2,8,8
What is one mole of a substance?
6.02 x 1023
List the activity series of metals in order of how easily they oxidized.
K,Na,Ca,Mg,Al,Zn,Fe,Sn,Pb,H,Cu,Hg,Ag,Au
State a chemical test you could use to distinguish between propanol and propanoic acid.
KMnO4/H+ add in propanol turn from purple to colorless.
Propanoic acid will not change.
Define the term Oxidizing agent and reducing agent.
Oxidizing agent - the reduced species
Reducing agent - oxidized species.
Draw the Lewis structure of methane.
Carbon should have 4 bonded pairs of electrons, and Hydrogen should have 1 pair of bonded electrons.
Calculate the percentage of carbon in acetylene, C2H2.
M(Ethyne) = 26g/mol
C= 24/26 x 100% = 92.3%
H= 2/26 x 100% = 7.69%
Name the two common allotropes of Carbon and describe their structure.
Diamond and Graphite.
Diamond arranged tetrahedrally where as Graphite is a 2D layer of sheets slide over each other.
With the aid of equations, distinguish between the reaction of ethene with Chlorine and ethyne with chlorine.
Ethene + Chlorine gives 1,2-dichloroethane.
Ethyne + Chlorine gives 1,2-dichloroethene + chlorine gives 1,1,2,2-tetrachloroethane.
Calculate the oxidation number of Sulfur in Sulfate ion.
+6
Explain the physical properties of Ionic substances/compounds in relation to its structure and bonding.
Ionic substances are hard and brittle and they are also good insulators. Ionic compounds such as salt NaCl conducts electricity in its molten state. And ionic compounds are related to how strong the positive and negative ions attract to each other.
An organic compound has a mass composition of 26.67% carbon, 2.22% hydrogen and 71.11% oxygen. Calculate the empirical formula of the compound.
n(C) = 26.6/12 = 2.217/2.217=1
n(H) = 2.22/1 = 2.22/2.217=1
n(O) = 71.11/16= 4.44/2.217=2
Explain the corrosion process.
Corrosion is the rusting of iron or formation of new compounds on metal surfaces. Water and Oxygen are conditions for corrosion.
Explain the process of polymerization with the help of equations.
Polymerization is the process of making plastics. Ethene + ethene gives polyethane units.
Write the balanced half equation for dichromate ion.
Explain what is meant by the term non-polar covalent bond and state and example.
A chemical bond that forms when electrons are shared equally between 2 atoms. H2, Cl2, Br2, Methane
Calculate how many grams of NaOH is needed for preparation of 250mL of 0.25 mol/L solution.
M(NaOH) = 40g/mol v= 250mL = 0.25L C= 0.25mol/L
C=n/v = n=cv n=(0.25)(0.25)=0.0625mol
n = m/M = m = nM = (0.0625)(40) = 2.5g
Identify the colors of the following precipitates.
Cu(OH)2, Fe(OH)2, BaSO4
Pale Blue, Green, White
Write the chemical equation for the production of ethanol from the hydration of ethene.
Ethene + water dilute H2SO4 Ethanol
List any 2 oxidizing agent.
Potassium Permanganate, Potassium Dichromate, Hydrogen peroxide, Bromine, Chlorine