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प्रश्न
Which of the following are ‘pure substances’ ?
Ice, Milk, Iron, Hydrochloric acid, Calcium oxide, Mercury, Brick, Wood, Air
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उत्तर
Iron and mercury are pure substances because these are elements. Hydrochloric acid, calcium oxide, and ice are also pure substances, as they are compounds.
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संबंधित प्रश्न
Which of the following materials fall in the category of a “pure substance”?
- Ice
- Milk
- Iron
- Hydrochloric Acid
- Calcium oxide
- Mercury
- Brick
- Wood
- Air
What is the scientific name of particles which make up mater?
When a crystal of potassium permanganate is placed in a beaker, its purple colour spreads throughout the water. What does this observation tell us about the nature of potassium permanganate and water?
What is meant by saying that metals are sonorous ?
Classify the following into elements and compounds :
- H2O
- He
- Cl2
- CO
- Co
Iron powder and sulphur powder were mixed together and divided into two parts A and B. When part A was heated strongly over a burner, then a substance C was formed. The part B was, however, not heated at all. When dilute hydrochloric acid was added to substance C, then gas D was evolved and when dilute hydrochloric acid was added to part B then gas E was evolved.
- What type of substance is B ?
- What type of substance is C ?
- Name the gas (i) D, and (ii) E ?
- State one characteristic property of gas D.
- Write one test to identify gas E.
What is the name of the clear liquid formed when a solid dissolves in a liquid ?
Fill in the following blank :
A colloid is a ..............mixture and its components can be separated by the technique known as ...............
Define Sol and give one example.
What is meant by a solution?
Milk of Magnesia is :
Which one of the following is not a chemical change ?
One of the following liquids will leave behind a residue on heating. This one is :
100 mL of water at room temperature of 25°C is taken in a beaker and a little of solid S is dissolved in it by stirring to obtain a solution X. More and more of solid S is added to the solution with constant stirring, while keeping the temperature of solution constant at 30°C. After some time it is observed that no more solid dissolves in water and at the same time some solid is also left undissolved at the bottom of the beaker.
- The contents of beaker are filtered through a filter paper to obtain solution Y in the form of a filtrate.
- What name is given to solutions like X ?
- What name is given to solutions like Y ?
- What will you observe if the solution Y at 30°C is cooled down to 10°C by keeping the beaker in crushed ice ? Why ?
- What term is used to denote the amount of solid dissolved in 100 grams of water in a solution lie Y ?
State whether the following statement are true or false :
Alcohol can be separated from a mixture of alcohol and water by a separating funnel.
Describe a method to separate a mixture of camphor and sand.
Intermolecular space is maximum in ______.
Define the term matter.
Write scientific reason.
Lemon sherbat has sweet, sour and salty taste and it can be poured in a glass.
Define the term matter.
