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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
उत्तर
symbols and formulae.
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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.
State whether the following statement is true or false. In case a statement is false, write the corrected statement.
Condensation of steam is not a chemical change.
Define precipitation.
FILL IN THE BLANK
Positively charged ions are called ........
TRUE \ FALSE
The evolution of a gas during a chemical reaction is shown by an arrow pointing downwards. True or false ?
How is precipitate formation in a chemical reaction indicated?
Write true or false :
Hydrogen sulphide has rotten egg smell .
Write true or false.
A chemical equation gives only qualitative information of a chemical reaction.
Write balanced chemical equations for the reactions represented by word equations in the conditions for chemical reaction.
Explain the following reaction with one suitable example of Double decomposition reaction.
Name the type of chemical reaction shown by the following equation:
2Mg + O2 → 2MgO
A solution of a substance ‘X’ is used for white washing Name the substance ‘X’ and write its formula.
Explain by writing a word equation.
Limestone powder disappears on adding to dilute hydrochloric acids.
Write the chemical reaction where the following changes are observed.
Physical state is changed
Give reason for the following:
Molybdenum is used in the manufacture of ammonia.
Define:
Electrochemical reaction
Give one example
State the original colour of the following substance and colour of residue obtained after heating.
Copper carbonate
What do you observe when Cobalt chloride paper is introduced in water vapour.
Distinguish by heating the following in dry test tubs.
Copper Sulphate and copper carbonate
Write your observation and a balanced equation in the case of the following substances being heated.
Ammonium dichromate.
Distinguish by dilute sulphuric acid.
Sodium Sulphite and sodium carbonate?
Give balanced equation for the following conversion affected by heat alone on the substance:
Zinc carbonate to zinc oxide
What is the role of a catalyst in a chemical reaction?
Which of the following is not an “element + element → compound” type reaction?
Anaerobic bacteria digest animal waste and produce biogas (Change – A). The biogas is then burnt as fuel (Change – B). The following statements pertain to these changes. Choose the correct one.
Chemists identify gypsum as a natural indicator.
Which of the following is/are true when milk changes into curd?
- Its state is changed from liquid to semi-solid.
- It changes colour.
- It changes the taste.
- The change cannot be reversed.
Choose the correct option from below:
State whether the following statements are true or false:
When a candle burns, both physical and chemical changes take place.
Give an example of a chemical reaction for each of the following situations:
A change in colour is observed.
