2013 LC Chemistry Before/After

Prodigious · 13-06-2013 4:49pm

To provide H+ ions for the reaction.

Define a primary standard.

Hamza Malik · 13-06-2013 4:52pm

Prodigious wrote: »

To provide H+ ions for the reaction.

Define a primary standard.

I said that answer in the mock and I got no marks.. Primary standard is a substance that can be available in a pure and stable form.

Prodigious · 13-06-2013 4:54pm

Hamza Malik wrote: »

I said that answer in the mock and I got no marks.. Primary standard is a substance that can be available in a pure and stable form.

Mocks are bull****.

What are the three stresses which LCP applies to?

outnumbered · 13-06-2013 4:57pm

Hamza Malik wrote: »

I said that answer in the mock and I got no marks.. Primary standard is a substance that can be available in a pure and stable form.

That's because, it's a source of H+ to enusre Mn+7 is fully reduced to Mn+2?

aoifemcg94 · 13-06-2013 4:57pm

Temperature
Pressure
Concentration
adding catalyst

CookieMonster.x · 13-06-2013 4:58pm

Prodigious wrote: »

Mocks are bull****.

What are the three stresses which LCP applies to?

Temperature, concentration and pressure.

What is the role of Mn+2 in titrations?

Slow Show · 13-06-2013 5:01pm

CookieMonster.x wrote: »

Temperature, concentration and pressure.

What is the role of Mn+2 in titrations?

It's an autocatalyst - catalyses the reaction.

Give two everyday uses of ethanoic acid.

comeclosa · 13-06-2013 5:08pm

Hamza Malik wrote: »

Wow I thought I was good at chemistry.. what's lcp ?

LCP = Le Chatelier's Principle
Ethanoic Acid uses= component of vinegar, used to make cellulose acetate, a component in photographic film.

Reagents needed for the sulfite/sulfate test?

Hamza Malik · 13-06-2013 5:11pm

comeclosa wrote: »

LCP = Le Chatelier's Principle
Ethanoic Acid uses= component of vinegar, used to make cellulose acetate, a component in photographic film.

Reagents needed for the sulfite/sulfate test?

A sulfite salt eg: Baruim cholride and Hcl. What's bod?

outnumbered · 13-06-2013 5:14pm

Hamza Malik wrote: »

A sulfite salt eg: Baruim cholride and Hcl. What's bod?

It is the levels of dissolved oxygen in a sample of water after being kept in the dark for 20 degrees for 5 days,

what's eutrophication?

Hamza Malik · 13-06-2013 5:19pm

outnumbered wrote: »

It is the levels of dissolved oxygen in a sample of water after being kept in the dark for 20 degrees for 5 days,

what's eutrophication?

It's the enrichment of the water with minerals causing an algal bloom which use up the O2 in water killing fish life.. sucks to be them :c

What's crystallisation? Eg, water of crystallisation?

outnumbered · 13-06-2013 5:25pm

It's water that is chemically combined in the formula of a compound?
What's gay-lussacs law?

Hamza Malik · 13-06-2013 5:31pm

outnumbered wrote: »

It's water that is chemically combined in the formula of a compound?
What's gay-lussacs law?

Gases are in the ratio of small whole numbers under stp.

Avagados law? The one with gases.

woopah92 · 13-06-2013 5:37pm

Hamza Malik wrote: »

Gases are in the ratio of small whole numbers under stp.

Avagados law? The one with gases.

Equal volumes of gases contain equal number of molecules provided they're measured under the same temp. and pressure.

Hess's law?

Prodigious · 13-06-2013 5:39pm

When a reaction takes place in anumber of stages, the sum of the heat changes of each stage is equal to the heat change if the reaction had been carried out in one stage.

Homologous series?

woopah92 · 13-06-2013 5:39pm

Oh and for gay-lussacs law that def might not get full marks, I'd say:
In a reaction between gases, the volumes of the gases and and any gaseous products formed are in the ratio of small whole number provided they're measured under the same conditions of temp and pressure.

woopah92 · 13-06-2013 5:46pm

Homologous series:
A series of compounds of uniform chemical type, that have the same method of preparation, have a general formula for it's members, show gradations in physical properties and differ from each previous member by a unit. I dunno if that's it fully though

Explain the word amphoteric and give an example of a substance which is amphoteric.

_LilyRose_ · 13-06-2013 5:48pm

woopah92 wrote: »

Homologous series:
A series of compounds of uniform chemical type, that have the same method of preparation, have a general formula for it's members, show gradations in physical properties and differ from each previous member by a unit. I dunno if that's it fully though

Explain the word amphoteric and give an example of a substance which is amphoteric.

A substance which can act as both an acid and a base...eg water is it?

Sequence of colour changes in titrations with starch indicator? (love this question for 12 marks!)

weirdspider · 13-06-2013 5:48pm

woopah92 wrote: »

Homologous series:
A series of compounds of uniform chemical type, that have the same method of preparation, have a general formula for it's members, show gradations in physical properties and differ from each previous member by a unit. I dunno if that's it fully though

Explain the word amphoteric and give an example of a substance which is amphoteric.

A substance that can act as an acid or a base eg water
State Pauli's Exclusion Principle

outnumbered · 13-06-2013 5:49pm

woopah92 wrote: »

Homologous series:
A series of compounds of uniform chemical type, that have the same method of preparation, have a general formula for it's members, show gradations in physical properties and differ from each previous member by a unit. I dunno if that's it fully though

Explain the word amphoteric and give an example of a substance which is amphoteric.

It is one which can act as either an Acid or a base depending on the subtance it's placed in. Eg. H2O
Define Electronegativity

weirdspider · 13-06-2013 5:50pm

_LilyRose_ wrote: »

A substance which can act as both an acid and a base...eg water is it?

Sequence of colour changes in titrations with starch indicator? (love this question for 12 marks!)

red/brown if iodine is used, pale yellow, blue black, colourless
Define atomic orbital

woopah92 · 13-06-2013 5:51pm

Region of space where there is a high probability of finding an electron :pac:

A triad?

outnumbered · 13-06-2013 5:52pm

weirdspider wrote: »

red/brown if iodine is used, pale yellow, blue black, colourless
Define atomic orbital

I thought it was Dark yellow, then straw yellow .........etc

SecondMan · 13-06-2013 5:54pm

weirdspider wrote: »

red/brown if iodine is used, pale yellow, blue black, colourless
Define atomic orbital

Region of space where you are most likely to find an electron.

What do flocculating agents do in water treatment and what flocculating agents are used?

weirdspider · 13-06-2013 5:55pm

outnumbered wrote: »

I thought it was Dark yellow, then straw yellow .........etc

Wait, which titration are you referring to? I just chose the iodine thiosulphate one and the colour of the conical flask is red/brown due to the liberated iodine

Hamza Malik · 13-06-2013 5:56pm

I bet you guys have chemistry books open in front you right now

weirdspider · 13-06-2013 5:56pm

SecondMan wrote: »

Region of space where you are most likely to find an electron.

What do flocculating agents do in water treatment and what flocculating agents are used?

They cause supsended particles to clump and aluminium sulphate
Who discovered the electron?

weirdspider · 13-06-2013 5:57pm

Hamza Malik wrote: »

I bet you guys have chemistry books open in front you right now

That would defeat the purpose of a quiz lol

SecondMan · 13-06-2013 5:59pm

weirdspider wrote: »

They cause supsended particles to clump and aluminium sulphate
Who discovered the electron?

Me

weirdspider · 13-06-2013 5:59pm

woopah92 wrote: »

Region of space where there is a high probability of finding an electron :pac:

A triad?

A group of 3 elements with similar properties where the weight of the middle element is approximately equal to the average of the other 2

***2013 LC Chemistry Before/After***

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2013 LC Chemistry Before/After