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OCR Salters F334 Chemistry of Materials (26/01/2011)

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Basic Oxygen Steeling Making Process.

All you need to know is... steel is at first full of impurities, they get rid of the sulphur with a blast of Magnesium. And get rid of other impurities like Carbon(which makes steel brittle) with a blast of oxygen. Different levels of other elements in the steel give it different properties.

Recycled steel is added to act as a coolant and a source of recycled steel.

You mean "SCRAP" steel is added as a coolant :smile:

Reply 161

smj14

ohh pheww i knew that! :biggrin:

(just didnt know it had an abbreviation :L) thanks for the explanation anyway though! good luck tomorrow :biggrin:

Reply 162

AGM

Original post by zahre

You mean "SCRAP" steel is added as a coolant :smile:

Ahhhh yes, indeed. Scrap steel.

Reply 163

limetang

Although examiners do like it if you say scrap steal helps prevent thermal shock.

Reply 164

tomio

could some one give me a rolemodel answer for how ph and temperature effects enzyme catalysed reaction.

Reply 165

limetang

I have a feeling we will get a question on protein synthesis.

More specifically translation, so anyone think it's a good idea to go through it?

Reply 166

smj14

aah i would really appreciate it if someone told me the conditions/reagents..? the ones before didnt seem to agree with each other!! *slightly panicking* ha

Reply 167

limetang

Original post by tomio

could some one give me a rolemodel answer for how ph and temperature effects enzyme catalysed reaction.

pH alters the ratio of COO- and NH+ groups in the molecule. This alters ionic interactions which hold together the tertiary structure. Altering these inTRA molecular forces (as they technically act on the same molecule) will alter the tertiary structure and active sites shape.

Temperature: At first as temperature increases more molecules will have sufficiant activation enthalpy to react in enzyme. As temperature increases it can break hydrogen bonds resulting in a change of shape of the active site meaning substrate can no longer bind to it.

Admitadely these aren't model answers but for pH you'll get marks for. Altering COO- and NH+. For talking about ionic interactions being altered and for talking about a shape change (specifically of the active site).

For temperature: More Energy= more colissions with the enzyme so higher rate. Too higher temperature breaks H bonds and alters the shape of the active site. No longer has complementary shape to substrate.

(edited 13 years ago)

Reply 168

limetang

Original post by smj14

aah i would really appreciate it if someone told me the conditions/reagents..? the ones before didnt seem to agree with each other!! *slightly panicking* ha

For Esterification CONCENTRATED H2SO4 (HCL may do but H2S04 is a stronger acid and basically you want this to be as concentrated as possible)

For acylation (reaction with acyl chloride and an alcohol/phenol) anhydrous conditions (or boom goes the reaction) at room temperature.

For Hydrolysis of esters. Mod Conc H2SO4 or HCL

Hydrolysis of amides: Mod conc acid/base

Both hydrolysis are done under reflux.

Reduction of carbonyl compounds, heat under reflux with NaBH4 (although don't stress about this as it is hardly asked and if it is asked you can find it on data sheet)

Reply 169

Lunaelu

Good luck everyone for tomorrow!

Don't worry I'll be helping by keeping the grade boundaries low :frown:

I'm so under prepared (why can't it be the legacy spec. I'm good at those exams and terrible at the new ones)

Reply 170

Rei5

how do u work out the rate constant?!? whats the formula?

Reply 171

brendan.

Right, I think it's time for bed.. if I want to actually get up in the morning. Looking forward to this exam and M1.. NAAAAAT. :biggrin:

Reply 172

zahre

Original post by Rei5

how do u work out the rate constant?!? whats the formula?

Rate = K [A] where A and B are the reactants or the catalyst. They give you the values and then you subsitute and rearrange the equation to work out a value for K.

Reply 173

xPixie

Original post by brendan.

Right, I think it's time for bed.. if I want to actually get up in the morning. Looking forward to this exam and M1.. NAAAAAT. :biggrin:

Moi aussi! :frown:

Sad Mechanics times :frown:

Thank god it'll be over by tomorrow (actually, today.. :tongue:

)
I'm aiming for a D in M1 :tongue:

Reply 174

gozatron

Hopefully protein synthesis does come up, the my biology revision will count for something after that poor excuse for an exam on Monday.

Good luck everyone!

Reply 175

xPixie

Original post by gozatron

Hopefully protein synthesis does come up, the my biology revision will count for something after that poor excuse for an exam on Monday.

Good luck everyone!

Gah me too! Hope TL comes up loadds :biggrin:

OCR Bio? If so, that peptide bond question :biggrin:

Good times

Reply 176

ABCDemily

Good luck everyone! I've revised my ass off for this one. I just want a nice long question on anything from thread of life, glass transition, or electrochemical cells. Any of those ridiculous 5 mark % questions can go suck themselves.

I'm trying not to cry. Brb, going to eat my weight in chocolate.