Advertisements
Advertisements
प्रश्न
What happens when cane sugar is strongly heated? Mention any two changes in it.
उत्तर
- Sugar is basically Sucrose.
- The molecular formula of Sugar is C12 H22O11 (or) C12(H2O)11.
- When sugar is heated, it loses all water molecules and decomposes to carbon.
- Chemical change;
- Irreversible change
APPEARS IN
संबंधित प्रश्न
FILL IN THE BLANK
In a ............ change, new substances are formed.
Write true or false .
A black residue is formed when sugar is heated .
Explain the following reaction with one suitable example of Displacement reaction.
Explain by writing a word equation.
Limestone powder disappears on adding to dilute hydrochloric acids.
Explain by writing a word equation.
Bubbles are seen on adding lemon juice to baking soda.
When electric current is passed through acidulated water ______ of water takes place.
Give a chemical test to distinguish between the following gases.
H2 and CO2
Give a chemical test to distinguish between the following gases.
HCl and Cl2
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 – Thermal decomposition of mercury [II] oxide.
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.
| Addition of dil. H2SO4 to KHCO3 | Name of residue obtained |
Name the solid residual product formed reaction and state its colour during – thermal decomposition of the following substance.
Lead nitrate.
Name the solid residual product formed reaction and state its colour during – thermal decomposition of the following substance.
Calcium hydroxide.
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
On heating calcium carbonate gets converted into calcium oxide and carbon dioxide.
(a) Is this a physical or a chemical change?
(b) Can you prepare one acidic and one basic solution by using the products formed in the above process? If so, write the chemical equation involved.
Which of the following statement is incorrect for a chemical reaction?
Give an example of a chemical reaction for each of the following situations:
A change in colour is observed.
Heat may evolve or be absorbed during a ______ change.
Iron and rust are the same substances.
______ is the chemical name of limestone.
