This is another section in O Level Chemistry where students find it tough to comprehend. Lets reveal the Secrets here.
An oxide is a compound of Oxygen and another element (e.g. through the process of Combustion)
• Metals form Metal Oxides and Non-Metals form Non-Metal Oxides
• Oxides can be classified as either Acidic, Basic, Amphoteric or Neutral
• Nature of the oxides of the elements across the periodic table from left to right changes from Basic –> Amphoteric –> Acidic
ACIDIC OXIDES
Examples:
SO2, SO3, CO2, NO2
Properties:
1. Do not react with acids.
2. React with bases and alkalis to form salt & water.
3. Dissolve in water to form acidic solutions.
4. Usually gases at room temp.
BASIC OXIDES
Examples:
Na2O, CaO, MgO, FeO, CuO
Properties:
1. Do not react with bases.
2. React with acids to form salt & water.
3. Basic Oxides are usually insoluble in water. Those that dissolve in water forms alkaline solutions.
NEUTRAL OXIDES
Examples:
CO, NO, H2O
Properties:
1. Neutral pH
AMPHOTERIC OXIDES
Examples:
Oxides formed with metals near “STEPS” such as ZnO, Al2O3, PbO,
Properties:
1. React with both acids and bases to form salt & water
For those taking GCE ‘O’ Level syllabus, there are many questions that will come out for this section on Types of Oxides.
Let’s take a look at some exam-based questions.
Quick Check 1:
Which of the following reacts with dilute sulphuric acid to give a gas and water as two of the products?
A. zinc
B. zinc carbonate
C. zinc hydroxide
D. zinc oxide
Quick Check 2:
Which element forms an oxide that reacts with water to give an acidic solution?
A. aluminium
B. sodium
C. sulphur
D. zinc
Quick Check 3:
Which element burns in air to form an oxide which, when shaken with water, gives a solution with a pH greater than 7?
A. carbon
B. hydrogen
C. magnesium
D. sulphur
PS: Do leave your suggested answers in the “Comments Section” directly below this post.
PPS: This post belongs to a series of blogposts that is associated with Secrets of “Acids, Bases & Salts and Qualitative Analysis revelaed”
The second qn should be sulphur since SO2 is acidic in nature.
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A. Zinc
C. sulphur
C. magnesium
I agree with the person above me, so I think the Qn.2 should be sulphur.
I also think that Qn.1 should be zinc because (if I’m not wrong) the Qn states that this reaction only forms two products and metal + acid — salt + H2 gas.
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sean Reply:
April 24th, 2009 at 3:46 pm
Hi Cydnie,
Good to see you participating cos “Wanting leads to Wanting, Doing leads to Having”.
These will be my suggested answers:
Question 1:
Ans: B cos question states that they want to see more than 2 products and only carbobate reacts with acid to give 3 products.
Question 2:
Ans: C cos Acidic Oxide are formed when a non-metal combines with oxygen.
Question 3:
Ans: C since Magnesium Oxide is the only Basic Oxide in the list and it will gives a pH higher than 7.
Hope this helps. Let me know if this chemistry blogsite has been helpful in any ways.
Keep Up The Good Work!
Sean =)
Reply
Hi Sherman, Gary & Cydnie,
Good to see you participating cos “Wanting leads to Wanting, Doing leads to Having”.
These will be my suggested answers:
Question 1:
Ans: B cos question states that they want to see more than 2 products and only carbobate reacts with acid to give 3 products.
Question 2:
Ans: C cos Acidic Oxide are formed when a non-metal combines with oxygen.
Question 3:
Ans: C since Magnesium Oxide is the only Basic Oxide in the list and it will gives a pH higher than 7.
Hope this helps. Let me know if this chemistry blogsite has been helpful in any ways.
Keep Up The Good Work!
Sean =)
Reply
my first answer is c: zincoxide becouse metaloxide+acid=salt and water always my second answer is S02 becouse its an acidic oxide. my third answer is magnesium couse its a metal and metaloxides are basic. base have a ph above then 7
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sean Reply:
April 24th, 2009 at 3:51 pm
Hi abdul rehman,
Thank you for your participation.
Answer for Q1 is B.
–> Note that question mentioned there will be at least 3 products.
Answer for Q2 is C.
–> you got it. Acidic Oxide indeed.
Answer for Q3 is C.
–> you got it. Cool!
Look forward to more participation from you.
To Your Academic Success in Chemistry,
Sean Chua
Master Trainer & Author
WINNERS Education Group
“Experience Learning with A Difference”
Reply
”Oxides formed with metals near “STEPS” such as ZnO, Al2O3, PbO,”
what do you mean by that?
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Anuja Reply:
March 31st, 2012 at 10:06 am
The “STEPS” are found in the periodic table, near the metalloids. So,aluminium, lead (11)and zinc (Found near metalloids) oxides are amphoteric oxides.
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gr8 site, really helped me out:D
my answer to question no. 1 is zinc carbonate because metal carbonates react with acids to form a salt, water and carbondioxide gas. My answer to ques. 2 is Sulphur oxide cuz its an acidic oxide and Ques. 3 is magnesium because it forms a basic oxide and when dissolved in water it will form an alkaline solution having a ph more than 7
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Ans: B cos question states that they want to see more than 2 products
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is sulphate a type of oxide?
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1. B because :
it gives off carbon dioxide (the gas)
it gives off water (the water(lol))
it also gives off a salt.
2. C because :
aluminum forms with oxygen to form an amphoteric solution, sodium forms a basic solution with water and so does zine. Through the process of elimination, sulphur is the only one that would fit this category.
3. C because :
carbon would form to create either carbon dioxide (acidic oxide) or carbon monoxide ( neutral oxide)
sulphur would form sulphur dioxide (acidic oxide)
hydrogen would form water when reacted with oxygen and i dont think its possible for hydrogen and oxygen to form hydroxide by themselves…so that leaves good ol’ C
magnesium is able to be gaseous and nonetheless if burned in air it would combine with oxygen to form a basic oxide which would dissolve in water to form an alkaline solution. — and its the only one which would have a pH greater than seven ANYWAY.
–Gr 11. Too bad it took me this long to find this awesome page… I have my Christmas final in Chemistry tomorrow and this was a good way to review.
–AshantiWasHere
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I think it D ….talking abut qs 1
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I agree with sean and bahamas the answers are
B
C
C
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