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Author Topic: Edexcel CHEMISTRY DOUBTS!!!!  (Read 254036 times)

Offline Igcseboy

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #120 on: May 19, 2010, 09:40:05 am »
Jan 2010 MCQ 11 an 12

for 11 how can we tell ??? (for the same types if come in exam)
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Offline Kim

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #121 on: May 19, 2010, 09:45:01 am »
Quote from: Igcseboy on May 19, 2010, 09:40:05 am
Jan 2010 MCQ 11 an 12

for 11 how can we tell ??? (for the same types if come in exam)

well for 12 the answer is A because mg is a metal and oxygen a non metal
and the bonding between a metal and non metal is ionic bonding
well for 11 the answer isC although i dunno why ill see if i can figure it out
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Offline Saladin

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #122 on: May 19, 2010, 10:14:52 am »
Quote from: Igcseboy on May 19, 2010, 09:40:05 am
Jan 2010 MCQ 11 an 12

for 11 how can we tell ??? (for the same types if come in exam)

For Question 12: The bonding between a metal and a non-metal is ionic. Thus A. But the further reason is that Mg and O bonding, there is almost no distortion of the ionic bond.

For Question 11: The nickel ion is green in color. And since it has a positive charge, it will go towards the negative electrode. The sulphate ion however, is colorless, and thus, even if it goes to the negative electrode, you cannot see it. Thus the answer is C.
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Offline Igcseboy

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #123 on: May 19, 2010, 04:21:45 pm »
Quote from: Engraved on May 19, 2010, 10:14:52 am
For Question 12: The bonding between a metal and a non-metal is ionic. Thus A. But the further reason is that Mg and O bonding, there is almost no distortion of the ionic bond.

For Question 11: The nickel ion is green in color. And since it has a positive charge, it will go towards the negative electrode. The sulphate ion however, is colorless, and thus, even if it goes to the negative electrode, you cannot see it. Thus the answer is C.

ok thanxx

but why MgO is not ionic covalent as there is distortion ????
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Offline Darth Austrakast

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #124 on: May 19, 2010, 04:25:23 pm »
yeah.......due to polarization
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Offline Igcseboy

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #125 on: May 19, 2010, 05:14:40 pm »
A pure hydrocarbon is used in bottled gas for cooking and heaing.

When 10cm^3 of the hydrocarbon is burned in 70 cm^3 of oxygen (in excess), the final gaseous mixture contains 30cm^3 carbondioxide and 20 cm^3 of unreacted Oxygen. All gaseous volumes are measured under identical conditions.

What is the formula of the hydrocarbon?

A.C2H6
B.C3H6
C.C3H8
D.C4H10

the answer is C... but how to get at this
i got this question in my mock exam



another one

Which of these sample of gas contains the same number of atoms as 1g of hydrogen gas?

A.22g of carbondioxide
B.8g of methane
C.20g of neon
D.8g of ozone(O3)

My teacher told the answer is C...... but am not sure  how to get at it???


any help will be appreciated :)
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Offline Kim

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #126 on: May 19, 2010, 05:46:02 pm »
well for the second one
1g of hydrogen has 1 mole
as 1/1=1
 the same for neon
20/20.2(molar mass)=0.99=1
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Offline Igcseboy

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #127 on: May 19, 2010, 05:52:53 pm »
Quote from: kim on May 19, 2010, 05:46:02 pm
well for the second one
1g of hydrogen has 1 mole
as 1/1=1
 the same for neon
20/20.2(molar mass)=0.99=1


but hydrogen is H2 right so the number of moles is 1/2=0.5 :S:S ????
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Offline Kim

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #128 on: May 19, 2010, 05:54:24 pm »
Quote from: Igcseboy on May 19, 2010, 05:52:53 pm

but hydrogen is H2 right so the number of moles is 1/2=0.5 :S:S ????
yup i forgot about that sorry
was just about to tell ya
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After all is said and done, more is said than done.

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Offline Igcseboy

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #129 on: May 19, 2010, 05:59:09 pm »
so ........... wat is correct????
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Offline Kim

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #130 on: May 19, 2010, 06:00:47 pm »
Quote from: Igcseboy on May 19, 2010, 05:59:09 pm
so ........... wat is correct????

u have to use h2 and Ne2 so follow austrakasts ans
i dunno if i got that name right lol
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Offline Saladin

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #131 on: May 19, 2010, 06:07:31 pm »
Quote from: Igcseboy on May 19, 2010, 05:14:40 pm
A pure hydrocarbon is used in bottled gas for cooking and heaing.

When 10cm^3 of the hydrocarbon is burned in 70 cm^3 of oxygen (in excess), the final gaseous mixture contains 30cm^3 carbondioxide and 20 cm^3 of unreacted Oxygen. All gaseous volumes are measured under identical conditions.

What is the formula of the hydrocarbon?

A.C2H6
B.C3H6
C.C3H8
D.C4H10

the answer is C... but how to get at this
i got this question in my mock exam



another one

Which of these sample of gas contains the same number of atoms as 1g of hydrogen gas?

A.22g of carbondioxide
B.8g of methane
C.20g of neon
D.8g of ozone(O3)

My teacher told the answer is C...... but am not sure  how to get at it???


any help will be appreciated :)

Hoping to answer this soon.
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Offline Saladin

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #132 on: May 19, 2010, 06:31:21 pm »
Quote from: Igcseboy on May 19, 2010, 05:14:40 pm
A pure hydrocarbon is used in bottled gas for cooking and heaing.

When 10cm^3 of the hydrocarbon is burned in 70 cm^3 of oxygen (in excess), the final gaseous mixture contains 30cm^3 carbondioxide and 20 cm^3 of unreacted Oxygen. All gaseous volumes are measured under identical conditions.

What is the formula of the hydrocarbon?

A.C2H6
B.C3H6
C.C3H8
D.C4H10

the answer is C... but how to get at this
i got this question in my mock exam



another one

Which of these sample of gas contains the same number of atoms as 1g of hydrogen gas?

A.22g of carbondioxide
B.8g of methane
C.20g of neon
D.8g of ozone(O3)

My teacher told the answer is C...... but am not sure  how to get at it???


any help will be appreciated :)

Can you please send me the actual question paper.
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Offline Saladin

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #133 on: May 19, 2010, 07:37:21 pm »
Quote from: Igcseboy on May 19, 2010, 05:14:40 pm
A pure hydrocarbon is used in bottled gas for cooking and heaing.

When 10cm^3 of the hydrocarbon is burned in 70 cm^3 of oxygen (in excess), the final gaseous mixture contains 30cm^3 carbondioxide and 20 cm^3 of unreacted Oxygen. All gaseous volumes are measured under identical conditions.

What is the formula of the hydrocarbon?

A.C2H6
B.C3H6
C.C3H8
D.C4H10

the answer is C... but how to get at this
i got this question in my mock exam



another one

Which of these sample of gas contains the same number of atoms as 1g of hydrogen gas?

A.22g of carbondioxide
B.8g of methane
C.20g of neon
D.8g of ozone(O3)

My teacher told the answer is C...... but am not sure  how to get at it???


any help will be appreciated :)

For (a) 3 moles of CO2 is formed. And 2 moles of O2 was used to form water. Thus 8 hydrogens were used.
Thus, C3H8

(b) 1 gram of H2 will mean 1 mole of H2. 20 grams of Ne will mean 1 mole of Ne. Thus same number of atoms as Hydrogen.
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Offline Kim

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #134 on: May 19, 2010, 07:53:15 pm »
hey cud sum1 tell the answer to jan 2009 q2
and how u got it??thanks
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After all is said and done, more is said than done.

By the time a man realizes that maybe his father was right, he usually has a son who thinks he’s wrong.

The early bird may get the worm, but the second mouse gets the cheese.
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