MTL 200 LAB 4 LEAD-TIN PHASE DIAGRAM
CERTIFICATION SCRIPT 2026 QUESTIONS
WITH SOLUTIONS GRADED A+
◍ The water phase diagram is best described as....
Answer: Unary
◍ Which loading is most likely to lead to unstable crack growth?.
Answer: Mode I
◍ procedure.
Answer: - samples of Excedrin and the four generic medications have been
dissolved and placed in dropper bottles - you will need just one or two drops
of the solution of the generic product you have been assigned, and also one
or two drops of the excedrin solution- these solutions should be put into two
separate small test tubes that have been carefully cleaned- be sure to label
the test tubes so that you know which solution is in which tube- the
stationary phase on the TLC plates is silica gel, and the mobile phase for this
experiment is ethyl acetate
◍ Modulus of Resilience (Ur).
Answer: Max elastic energy (per unit volume) material can absorb without
perm deformation-Area under elastic region
◍ how to write the Rf value in your lab notebook.
Answer: - the Rf value of a particular compound will be different when
analyzed using different TLC systems - so it is always essential when
reporting an Rf value that the mobile phase and stationary phase are
included- for example: The Rf of compound X was found to be 0.37 in a
TLC system of silica gel and hexane. - the Rf value has no units because the
units used in the measurements cancel out in the calculation - also, the Rf
, value will always be less than 1
◍ how can TLC monitor the progress of a reaction?.
Answer: - by sampling a reaction from time to time, it is possible to watch
the reactants disappear and the products appear using TLC- this provides the
experimenter with the ability to determine if a reaction is proceeding, and
when it is complete
◍ how should the TLC plate be positioned in the jar?.
Answer: - the plate must be carefully set into the jar so that it is standing up
in a vertical position- let the plate lean against the inside of the jar and screw
the cap on
◍ spotting the samples.
Answer: - make a small pencil Mark on the TLC plate, approximately 1cm
from the bottom at the point(s) you intend to apply the test solution(s). Do
not use a pen, the organic compounds in the ink will interfere with your
analysis of the results - the application of the sample solution is called
spotting because you are making a spot on the TLC plate - the spotting
solution is an approximate 1% solution of the substances being analyzed -
when spotting, it is extremely important that the spots be as small as
possible and clearly visible when applied to the TLC plate - sample
solutions are spotted on the TLC plate using micropipettes (essentially a
very small glass straw)
◍ 1.3 Transgranular fracture.
Answer: Fracture along crystallographic planes or more specifically cuts
across the grains
◍ 1.3 What does the surface of 1018N look like at the fracture?.
Answer: Ductile fracture, covered in "cups and cones" as well as dimples.
◍ 1.1 Effects of Carbon Content.
Answer: Carbon added interstitally (smaller carbon atoms fit between larger
iron atoms)-Increase strength, harness-decrease ductility
◍ what is the Rf value.
CERTIFICATION SCRIPT 2026 QUESTIONS
WITH SOLUTIONS GRADED A+
◍ The water phase diagram is best described as....
Answer: Unary
◍ Which loading is most likely to lead to unstable crack growth?.
Answer: Mode I
◍ procedure.
Answer: - samples of Excedrin and the four generic medications have been
dissolved and placed in dropper bottles - you will need just one or two drops
of the solution of the generic product you have been assigned, and also one
or two drops of the excedrin solution- these solutions should be put into two
separate small test tubes that have been carefully cleaned- be sure to label
the test tubes so that you know which solution is in which tube- the
stationary phase on the TLC plates is silica gel, and the mobile phase for this
experiment is ethyl acetate
◍ Modulus of Resilience (Ur).
Answer: Max elastic energy (per unit volume) material can absorb without
perm deformation-Area under elastic region
◍ how to write the Rf value in your lab notebook.
Answer: - the Rf value of a particular compound will be different when
analyzed using different TLC systems - so it is always essential when
reporting an Rf value that the mobile phase and stationary phase are
included- for example: The Rf of compound X was found to be 0.37 in a
TLC system of silica gel and hexane. - the Rf value has no units because the
units used in the measurements cancel out in the calculation - also, the Rf
, value will always be less than 1
◍ how can TLC monitor the progress of a reaction?.
Answer: - by sampling a reaction from time to time, it is possible to watch
the reactants disappear and the products appear using TLC- this provides the
experimenter with the ability to determine if a reaction is proceeding, and
when it is complete
◍ how should the TLC plate be positioned in the jar?.
Answer: - the plate must be carefully set into the jar so that it is standing up
in a vertical position- let the plate lean against the inside of the jar and screw
the cap on
◍ spotting the samples.
Answer: - make a small pencil Mark on the TLC plate, approximately 1cm
from the bottom at the point(s) you intend to apply the test solution(s). Do
not use a pen, the organic compounds in the ink will interfere with your
analysis of the results - the application of the sample solution is called
spotting because you are making a spot on the TLC plate - the spotting
solution is an approximate 1% solution of the substances being analyzed -
when spotting, it is extremely important that the spots be as small as
possible and clearly visible when applied to the TLC plate - sample
solutions are spotted on the TLC plate using micropipettes (essentially a
very small glass straw)
◍ 1.3 Transgranular fracture.
Answer: Fracture along crystallographic planes or more specifically cuts
across the grains
◍ 1.3 What does the surface of 1018N look like at the fracture?.
Answer: Ductile fracture, covered in "cups and cones" as well as dimples.
◍ 1.1 Effects of Carbon Content.
Answer: Carbon added interstitally (smaller carbon atoms fit between larger
iron atoms)-Increase strength, harness-decrease ductility
◍ what is the Rf value.
