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प्रश्न
A chemical equation is a statement that describes a chemical change in terms of
पर्याय
symbols and formulae
energy
number of atoms
colours
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उत्तर
symbols and formulae.
APPEARS IN
संबंधित प्रश्न
When baking soda is mixed with lemon juice, bubbles are formed with the evolution of a gas. What type of change is it? Explain.
The gas we use in the kitchen is called liquefied petroleum gas (LPG). In the cylinder, it exists as a liquid. When it comes out from the cylinder it becomes a gas (Change − A), then it burns (Change − B). The following statements pertain to these changes. Choose the correct one.
Complete and balance the following chemical equations:
N2 + O2 →
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
........... electrolytes dissociate completely in aqueous state and allow large amount of electricity to flow through it.
TRUE \ FALSE
Temperature at which a liquid starts boiling is known as the boiling point of that liquid. True or false ?
True or false
New substances are formed in a chemical change.
Fill in the blank:
The basic conditions necessary for a chemical reaction is _______
Write true or false.
A chemical equation gives only qualitative information of a chemical reaction.
State what you would observe when the following substance is heated in a glass test tube Copper (II) carbonate Red lead .
Explain by writing a word equation.
Respiration is a chemical change.
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 |
Write your observation and a balanced equation in the case of the following substances being heated.
Zinc carbonate.
Give a word equation for the following reaction.
An exothermic reaction where both the reactants are gases, one of which is oxygen.
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 water to quicklime.
Give balanced equation for the following conversion affected by heat alone on the substance:
Zinc nitrate to nitrogen dioxide
Classify the following as physical or chemical properties
Zinc dissolves in hydrochloric acid with the evolution of hydrogen gas.
Which of the following is a chemical change?
Iron benches kept in lawns and gardens get____________. It is a _________ change because a new _________ is formed.
