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प्रश्न
Fill in the blank
A new substance is always formed in a _______ change.
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उत्तर
A new substance is always formed in a chemical change.
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संबंधित प्रश्न
When carbon dioxide is passed through lime water, it turns milky due to the formation of ______.
Complete and balance the following chemical equations
NaCI + `AgNO_3` `→`
Complete and balance the following chemical equations:
Ba`"CI"_2` + `"H"_2"SO"_4` `→`
(aq.) (aq.)
Write the missing reactants and products and balance the equations.
................+ HCI `→` NaCI + `"H"_2"O"` + .........................
Complete the statement by filling the gap using an appropriate term from the terms given in the bracket.
(slow, coloured, arrow, fast, smell, milky, physical, product, chemical, reactant, covalent, ionic, octet, duplet, exchange, sharing, equality sign)
An ______ is drawn in between the reactants and products while writing the equation for a chemical reaction.
Complete and balance the following reaction:
\[\ce{Pb(NO3)2 ->[\Delta]}\]
Distinguish by heating the following in dry test tubs.
Copper Sulphate and copper carbonate
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.
Complete the table given below.
| Heat on copper carbonate | Test for gas evolved |
Complete the table given below.
| Addition of dil. H2SO4 to FeS | Odour of gas evolved |
Explain the Silver nitrate solution is kept in coloured reagent bottles in the laboratory.
Higher order Thinking question
A very hot glass on putting in cold water cracks. What does this change indicate?
Discuss how acid rain occurs due to emission of smoke from vehicles and industries?
The percentage composition of Nitrogen in Ureas is ______.
Chemists identify gypsum as a natural indicator.
Write some materials prepared by chemical changes.
Two chemical species X and Y combine together to form a product P which contains both X and Y
\[\ce{X + Y -> P}\]
X and Y cannot be broken down into simpler substances by simple chemical reactions. Which of the following concerning the species X, Y and P are correct?
(i) P is a compound
(ii) X and Y are compounds
(iii) X and Y are elements
(iv) P has a fixed composition
Classify the following as physical or chemical properties
Most metal oxides form alkalis on interacting with water.
When magnesium is burnt in the air, a new substance is formed which is ______.
Give an example where heat, light, and sound are produced during a chemical change.
