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सी.आई.एस.सी.ई.आईसीएसई ICSE Class 7

State What You Would Observe When the Following Substance is Heated in a Glass Test Tube Red Lead - Chemistry

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प्रश्न

State what you would observe when the following substance is heated in a glass test tube red lead.

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उत्तर

2Pb3O4 → 6PbO + O2 ↑
The dark red lead as red powder changes to yellow colour. The yellow colour residue on further heating sticks to the tube and give reddish colour to glass. A colourless and odourless gas is evolved.

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अध्याय 5: Language of Chemistry - Additional questions

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सेलिना Concise Chemistry [English] Class 7 ICSE
अध्याय 5 Language of Chemistry
Additional questions | Q 6.1

संबंधित प्रश्न

State whether the following statement is true or false. In case a statement is false, write the corrected statement.

Formation of manure from leaves is a physical change.


The gas we use in the kitchen is called liquefied petroleum gas (LPG). In the cylinder, it exists as a liquid. When it comes out from the cylinder it becomes a gas (Change − A), then it burns (Change − B). The following statements pertain to these changes. Choose the correct one.


MULTIPLE CHOICE QUESTIONS

Tick the most appropriate answer.

Compounds, which in their molten state allow an electric current to pass through them are called

  1. electrolytes
  2. non-electrolytes
  3. non-conductors
  4. none of these

FILL IN THE BLANK

A .............. change is a temporary change.


What are biocatalysts ?


Is kerosene an electrolyte or a non-electrolyte ?


Explain the type of reactions on the basis of the direction of reaction.


 Fill in the blank

A new substance is formed in a _______ change.


Write true or false  :
No new substance is formed during a chemical reaction.


Write true or false :

When iron and sulphur are heated together a grey mass is formed which is attracted by a magnet .


Copper carbonate when heated, it turns :


Show with the help of diagram of electronic configuration how the following compound is formed from the constituent atoms.

Water


What do you observe? When

Sodium chloride solution is added to silver nitrate solution.


Name: A brown gas 


State the original colour of the following substance and colour of residue obtained after heating.

Ammonium dichromate


Give a chemical test to distinguish between the following gases. 

CO2 and SO2


Write your observation and a balanced equation in the case of the following substances being heated.

Copper carbonate.


Distinguish by dilute sulphuric acid.

Sodium sulphide and sodium sulphite?


Select the correct answer for the following options:

The gas which reacts with oxygen to give a neutral liquid.


On heating which of the following substances i.e. copper carbonate, zinc carbonate, washing soda, copper sulphate, zinc nitrate, copper nitrate, lead nitrate, ammonium chloride and ammonium dichromate – relate to the reaction given below.

A white solid which evolves two colourless gases which on cooling combine and condense on the cooler parts of the test tube.


Complete the table given below.

Heat on  copper carbonate Test for gas evolved  

State the following reaction represent oxidation or reduction.

\[\ce{Cl- ->Cl}\]


Give a balanced equation for the conversion of an ammonium salt to a basic gas.


Burning of paper is a ______ change.


Chemical change is a temporary change.


Rusting of Iron: undesirable change:: Dead plants turn into manure: ______.


Vanaspati is obtained from vegetable oils by the addition of ______ to the oils.


Heat may evolve or be absorbed during a ______ change.


The chemical formula of rust is ______.


Give an example where heat, light, and sound are produced during a chemical change.


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