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What is the best method to classify a chemical substance? - Coggle Diagram
What is the best method to classify a chemical substance?
classifiers
conductivity
conductive when dissolved in water = ionic compound
not conductive = non metal
conductive when dry = metal
type of substance
organic
inorganic
shape
regular
ionic compounds are brittle, break in regular shapes (i.e. sodium chloride)
metals are malleable and ductile, can be found in strips/wires
irregular
metals are malleable, but likely found in clusters/irregular chunks
form
solid
fixed shape
liquid
no fixed shape, reforms to fit container
gas
mixture
chemical compounds
metals
malleable
ability to be reshaped through force
have luster when sanded
ductile
ability to be stretched out into wires
conductive when dry
good heat conductors
non-metals
dull
covalent bonds
brittle
poor conductors
high ionisation energy and electronegativity
ionic compounds
usually brittle
ionic bonds are built when atoms share transfer electrons - if a negatively charged atom is displaced and slides close to another negatively charged atom, it produces a force that pushes them apart
usually can dissolve in water
high melting point
high boiling point
classification
element
metals
metallic bonding
non metals
covalent bonding
compounds
non metal + metal
ionic bonding
mixture
contents
a physical blend of 2 or more substances that can exist within themselves
deconstruct
what is a chemical substance?
a chemical substance is any compound or element that has a consistent composition and structure
depending on the bond, a chemical substance's properties can vary due to the type of bond
how do you classify a chemical substance?
chemical substances can be identified and classified through a series of tests which confirm different properties of specific categories
for example, running a conductivity test when the substance is dry/dissolved in water would determine whether it is a metal (conductive when dry) or an ionic compound (conductive when dissolved in water)
how will each method be proved effective?
time taken to conduct the method
reliability of the results
difficulty of which the results can be gathered
methods for classification
conductivity
use a conductivity probe to test for electrical conductivity
if not electrically conductive when dry, submerge in water
test for conductivity again
conductivity is a factor that can determine the substance's compound form
melting and boiling point
exposing the substance to heat
if the substance is a liquid, it can be placed in a beaker and held above
hardness and malleability
if the substance breaks easily, it is brittle
if the substance does not break but dents, it is malleable
use a board and hammer to lightly hammer the substance (IF SOLID)
solubility
submerge in water
if the substance dissolves, it is water soluble
luster
does the substance appear shiny without sanding?
when sanded, does the substance appear shiny?
can the substance be described as dull?
the appearance of the substance in terms of luster can assist in determining the chemical bond of the substance
expected outcomes/dependent variables
using the results gathered, it should become easier to assume the type of bond that occurs within the structure of the substance
the assumption SHOULD BE MADE using correct scientific evaluation and knowledge
i.e. putting together the different results from a test, and knowing it is an ionic bond because of the properties that the substance displayed.
variables to consider
environment
is the environment that all the experiments are conducted in consistent?
what variables affect the consistency?
temperature
lighting (sun, heat, direct light, colour of light)
controlled variables
consistent amount of water/heat applied etc. when conducting tests
temperature of bunsen burner
amount of the substance used
because different types of bonding can display the same properties and characteristics, how will the observations provide a clear difference between these types of bonds?