Due to its hardness, thermal stability, and resistance to wear,
silicon nitride is used in cutting tools. It can be produced
through the following chemical reaction. 3 Si(s) + 2 N2(g) „³
Si3N4(s) A combination of 123 g of N2 and 160 g Si is used.
a. What is the theoretical yield of silicon nitride?
b. What mass of the excess reactant remains after the reaction
is allowed to progress?
Silicon nitride (Si3N4) is made by combining elemental silicon
with nitrogen gas at a high temperature. a.) How many grams of
silicon are needed to react with an excess of nitrogen to prepare
150. grams of silicon nitride? b.) How many grams of nitrogen would
need to react? c.) If you determine that 0.950 moles of silicon
nitride were formed in this reaction, what would be the percent
yield? Give two possible explanations for why the percent yield
would be...
Silcon dioxide (SiO2) has a molecular density of 2.3
x 1022 molecules/cm3. So for, silicon
nitride, what is it's molecular density in terms of
molecules/cm3?
Provide a sketch of how the tensile strength and the hardness of
a simple Fe-C alloy changes as the carbon content is varied.
Details the reasons behind the responses that you have sketched –
ensuring you relate these to the relevant diagrams.
Excellent combinations of hardness, strength, and toughness are
obtained from
tempered martensite. An employee in a heat treatment facility
austenitized an eutectoid
steel at 9500C for 45 min and finally allowed the steel to slowly
cooled in furnace. Do
you think the required tempered martensite structure was produced?
If not, support
your answer with a detail heat treatment that can be employed for
the steel.
Discuss the variation of tensile strength, elongation, Vickers
hardness and fracture toughness with C (carbon) % for normalised
carbon steels. Write 500 words
The
water quenched 1045 sample had a higher hardness and tensile
strength than the air cooled sample? Explain in term of
microstructural theory as to why this is the case.