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प्रश्न
A chemical equation is a statement that describes a chemical change in terms of
विकल्प
symbols and formulae
energy
number of atoms
colours
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उत्तर
symbols and formulae.
APPEARS IN
संबंधित प्रश्न
State whether the following statement is true or false. In case a statement is false, write the corrected statement.
Iron pipes coated with zinc do not get rusted easily.
When baking soda is mixed with lemon juice, bubbles are formed with the evolution of a gas. What type of change is it? Explain.
MULTIPLE CHOICE QUESTIONS
Tick the most appropriate answer.
Compounds, which in their molten state allow an electric current to pass through them are called
- electrolytes
- non-electrolytes
- non-conductors
- none of these
FILL IN THE BLANK
Negatively charged ions are called ..........
TRUE \ FALSE
Electrolytic refining is a method in which a thin coating of a metal is done over another metal.
What do you observe when :
an iron nail is kept in tap water for few days
State what you would observe when the following substance is heated in a glass test tube Copper (II) carbonate Red lead .
Name the type of chemical reaction shown by the following equation:
2Mg + O2 → 2MgO
Show with the help of diagram of electronic configuration how the following compound is formed from the constituent atoms.
Hydrogen chloride
Distinguish by heating the following in dry test tubs.
Ammonium Chloride and iodine.
What do you observe when CO2 is passed through lime water first and then a little in excess.
Write your observation and a balanced equation in the case of the following substances being heated.
Ammonium chloride
A chemical reaction is often accompanied by external indications or characteristics which include –
- Colour change
- Effervescence or gas evolved
- Evolution or absorption of heat
- Formation of a precipitate.
With reference to each of the above indications, state the external indication seen during – Addition of dilute acid to an active metal.
Explain the term chemical reaction with special reference to reactants and products.
Explain with the help of balanced equations, how precipitation reactions are used for identifying the positive radicals in three different salts, each having a different cation [positive ion].
NPK are the primary nutrients for plants.
Classify the following processes into physical or chemical changes:
- Beating of aluminium metal to make aluminium foil.
- Digestion of food.
- Cutting of a log of wood into pieces.
- Burning of crackers.
The chemical name of baking soda is sodium bicarbonate.
The reaction of H2 gas with oxygen gas to form water is an example of ______.
Both CO2 and H2 gases are ______.
