Chem Mcq... | Page 5 - XtremePapers

XtremePapers

• Home What's new Latest activity Authors
• Papers CAIE Edexcel IELTS SAT IB
• Forums New posts Search forums
• Revision
• What's new New posts New profile posts Latest activity
• Members Current visitors New profile posts Search profile posts

Log in Register What's new Search

Search

Everywhere Threads This forum This thread Search titles only By: Search Advanced search…

• New posts
• Search forums

Menu Log in Register Navigation Install the app Install More options Contact us Close Menu

• We need your support!

  We are currently struggling to cover the operational costs of Xtremepapers, as a result we might have to shut this website down. Please donate if we have helped you and help make a difference in other students' lives! Click here to Donate Now (View Announcement)

• Home
• Forums
• Qualifications, Exams & Tests
• A-Levels

You are using an out of date browser. It may not display this or other websites correctly.You should upgrade or use an alternative browser. chem mcq...

• Thread starter hassam
• Start date May 24, 2011

Prev

• 1
• 2
• 3
• 4
• 5
• 6
• 7
• 8
• 9

Next First Prev 5 of 9

Go to page

Go Next Last

sweetiepie

Messages 4,291 Reaction score 6,457 Points 523 yeah bt how wil we calculate plz telme m really weak in chemistry ... X

xHazeMx

Messages 426 Reaction score 4 Points 0 N2O4 has 0.02 moles which is given in the question. NaOH will have twice that moles as u see (2) beside the NaOH in the equation so ( 2 x 0.02 = 0.04 ) this is for the moles part ( n ) the concentration is already given in the question which is 0.5. now use the formula ( C= n/v ) .. ( C is the concentration and n is the number of moles ) .. put each value in the equation and find volume u will get it 0.08 dm^3 which is the same as 80 cm^3 did u get that ?

sweetiepie

Messages 4,291 Reaction score 6,457 Points 523 yeah i calculated so i got it thank u..... now explain me q.8 of same m/j 2006???? X

xHazeMx

Messages 426 Reaction score 4 Points 0

sweetiepie said: yeah i calculated so i got it thank u..... now explain me q.8 of same m/j 2006???? Click to expand...

u welcome sorry i have to go now. i will help u with more questions later

sweetiepie

Messages 4,291 Reaction score 6,457 Points 523 no prb...

sweetiepie

Messages 4,291 Reaction score 6,457 Points 523 is there any1 esle to explain me???? H

hassam

Messages 2,619 Reaction score 293 Points 93 wat?>

MHHaider707

Messages 118 Reaction score 2 Points 28 Answer is A!! Transformation from X to Y Enthalpy change is positive that means, Y has got higher energy content than X now transformation from Y to Z enthalpy change is negative which means, Z has got less energy content than Y, which is best represented by option A!!! In such questions in which we have to show energy profile diagram of two reactions, there are always two peaks in the diagram!!! So answer is A.... got it???

sweetiepie

Messages 4,291 Reaction score 6,457 Points 523 yeah thank u... H

hassam

Messages 2,619 Reaction score 293 Points 93 39 Which compounds are able to react with concentrated sulphuric acid to give a product that will decolourise acidic potassium manganate(VII)? 1 (CH3)3COH 2 CH3CH2CH(OH)CH3 3 CH3CO2H cn any body tell me wats reaction of conc. sulfuric acid with carboxylic acid

MHHaider707

Messages 118 Reaction score 2 Points 28

sweetiepie said: yeah thank u... Click to expand...

no problem S

sheikfathiu

Messages 13 Reaction score 0 Points 0 i think it its 1 2 3

alisha

Messages 393 Reaction score 21 Points 28

hassam said: 39 Which compounds are able to react with concentrated sulphuric acid to give a product that will decolourise acidic potassium manganate(VII)? 1 (CH3)3COH 2 CH3CH2CH(OH)CH3 3 CH3CO2H cn any body tell me wats reaction of conc. sulfuric acid with carboxylic acid Click to expand...

I think its only 1 and 2. they are both alcohols and conc. H2SO4 is a dehydrating agent, so if a water molecule is removed you will get alkenes. Alkenes will decolourize potassium manganate because they can get oxidized to ketones/aldehydes/ carboxylic acids depending on the conditions. But 3 is an ester and it will get hydrolyzed by dilute H2SO4 and not conc. In the presence of H2SO4 (conc) carboxylic acids will react with alcohols to form esters, other than that i dont know. H

Hateexams93

Messages 286 Reaction score 4 Points 0 12 Which chlorine compound has bonding that can be described as ionic with some covalent character? A NaCl B MgCl2 C AlCl3 D SiCl4 WHY ITS B ? S

sniper7137

Messages 67 Reaction score 7 Points 18

alisha said:

hassam said: 39 Which compounds are able to react with concentrated sulphuric acid to give a product that will decolourise acidic potassium manganate(VII)? 1 (CH3)3COH 2 CH3CH2CH(OH)CH3 3 CH3CO2H cn any body tell me wats reaction of conc. sulfuric acid with carboxylic acid Click to expand...

I think its only 1 and 2. they are both alcohols and conc. H2SO4 is a dehydrating agent, so if a water molecule is removed you will get alkenes. Alkenes will decolourize potassium manganate because they can get oxidized to ketones/aldehydes/ carboxylic acids depending on the conditions. But 3 is an ester and it will get hydrolyzed by dilute H2SO4 and not conc. In the presence of H2SO4 (conc) carboxylic acids will react with alcohols to form esters, other than that i dont know. Click to expand...

I think the question is talking about the formation of alkenes from alcohols in the presence of H2SO4. I think it is A and B only are correct as alcohols >> alkenes >> aldehydes / ketones due to cleavage of double bond.

alisha

Messages 393 Reaction score 21 Points 28

Hateexams93 said: 12 Which chlorine compound has bonding that can be described as ionic with some covalent character? A NaCl B MgCl2 C AlCl3 D SiCl4 WHY ITS B ? Click to expand...

NaCl is entirely ionic, MgCl2 is ionic with some degree of covalency, AlCl3 is ionic with a great degree of covalency (due to dative bond and all) SiCl4 is covalent. this should be remembered. it is in periodicity. A

ambitious1

Messages 26 Reaction score 0 Points 0 Hey all, Can someone please state the answer for Q.11, and explain why is it so? Thanks! =)

alisha

Messages 393 Reaction score 21 Points 28 wich paper? A

ambitious1

Messages 26 Reaction score 0 Points 0 It's the first question posted in the forum, page 1.

alisha

Messages 393 Reaction score 21 Points 28 i think it is B becoz initially the reaction is uncatalyzed and proceeds normally, but as products are formed and one of the product is a catalyst, the rate of reaction is increased so the line gets steeper. They say the answer is c because the product is used up so the rate of reaction decreases, but isnt the rate of reaction actually a measure of how fast the reactants are converted to products? whether the product remains or not is not a problem. Prev

• 1
• 2
• 3
• 4
• 5
• 6
• 7
• 8
• 9

Next First Prev 5 of 9

Go to page

Go Next Last You must log in or register to reply here. Share: Facebook Twitter Reddit Pinterest Tumblr WhatsApp Email Share Link

• Home
• Forums
• Qualifications, Exams & Tests
• A-Levels

• We need your support!

  For almost 10 years, the site XtremePapers has been trying very hard to serve its users. However, we are now struggling to cover its operational costs due to unforeseen circumstances. If we helped you in any way, kindly contribute and be the part of this effort. No act of kindness, no matter how small, is ever wasted. Click here to Donate Now

Top