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प्रश्न
True or false
New substances are formed in a chemical change.
विकल्प
True
False
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उत्तर
True
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संबंधित प्रश्न
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In a ............ change, new substances are formed.
Is kerosene an electrolyte or a non-electrolyte ?
Choose the correct option from the bracket and explain the statement giving reason.
(Oxidation, displacement, electrolysis, reduction, zinc, copper, double displacement, decomposition)
To prevent rusting, a layer of ______ metal is applied on iron sheets.
Give an example of a reaction where the following are involved:
Solution
When hydrogen burns in oxygen, water is formed; when electricity is passed through water, hydrogen and oxygen are given out. Name the type of chemical change involved in the two cases.
Complete and balance the following reaction:
\[\ce{NH3 + O2 ->[\Delta]}\]
What is observed in performing the following :
| Hydrogen | Oxygen | Carbon dioxide | Chlorine | |
| Litmus test | ||||
| Apply a burning splint to the gas | ||||
| Colour of gas | colourless | colourless | colourless | greenish-yellow |
| Odour of gas |
What do you observe when HCI is passed through a silver nitrate solution.
Give examples of exothermic reactions i.e. heat evolved in each of the following:
(a) reaction between a solid and a liquid
(b) reaction between two gases
Give two examples of exothermic reactions seen in everyday life.
Give balanced equation for the following conversion affected by heat alone on the substance:
Zinc carbonate to zinc oxide
Complete the table given below.
| Heat on ammonium dichromate | Name of neutral gas evolved |
State the following reaction represent oxidation or reduction.
\[\ce{Fe++->Fe+++}\]
Give a balanced equation for the conversion of an ammonium salt to a basic gas.
Select the correct answer from the options given below:
State the gaseous product formed, when
An ammonium salt reacts with an alkali.
True or False. If false, give the correct answer.
Taking a glass of water and freezing it by placing it in the freezer is a chemical change.
A reaction between an acid and a base is called ______.
Chemical change is a temporary change.
If you leave a piece of iron in the open for a few days, it acquires a film of brownish substance, called rust.
Can you change rust back into iron by some simple method?
Write a note on the catalyst.
Write a note on the following:
Fermentation
