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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.
APPEARS IN
संबंधित प्रश्न
How do the following help in bringing about a chemical change?
pressure.
Name three biochemical catalysts found in the human body.
Write the missing reactants and products and balance the equations.
NaOH + ............... `→` NaCI + ...................
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
The evolution of a gas during a chemical reaction is shown by an arrow pointing downwards. True or false ?
Name the type of chemical reaction shown by the following equation:
CaCO3 → CaO + CO2
Explain by writing a word equation.
Respiration is a chemical change.
Show with the help of diagram of electronic configuration how the following compound is formed from the constituent atoms.
Sodium chloride
What do you observe when H2S is passed through a lead nitrate solution.
Explain the term ‘chemical reaction’ with special reference to – ‘reactants’ and ‘products’.
Give examples of exothermic reactions i.e. heat evolved in each of the following:
(a) reaction between a solid and a liquid
(b) reaction between two gases
Give two examples of exothermic reactions seen in everyday life.
Give reason for the following:
Electrolytic decomposition of water is a reaction involving change of state.
Give a balanced equation for a reaction involving the evolution of gas on the addition of dilute acid to calcium carbonate.
Higher order Thinking question
Peeled and unpeeled banana does not look the same. Does that mean peeling banana is a chemical change?
Classify the following as physical or chemical properties
Most metal oxides form alkalis on interacting with water.
A student took a solution of copper sulphate in a beaker and put a clean iron nail into it and left it for about an hour.
Are these changes chemical in nature?
When magnesium is burnt in the air, a new substance is formed which is ______.
Write a note on the following:
Fermentation
The reaction of H2 gas with oxygen gas to form water is an example of ______.
