Matter & Mixtures — Set 5
Chemistry · पदार्थ और मिश्रण · Questions 41–50 of 50
What is the process of converting a liquid into its vapor below its boiling point?
Correct Answer: B. Evaporation
Evaporation is a surface phenomenon where liquid turns into vapor at any temperature below the boiling point. It causes cooling as high-energy particles escape the liquid surface. Factors like surface area and wind speed affect the rate of evaporation.
Which of the following is the most abundant gas in the Earth's atmosphere?
Correct Answer: B. Nitrogen
Nitrogen makes up approximately 78% of the Earth's atmosphere by volume. It is a relatively inert gas that is essential for life processes but must be fixed into compounds. Oxygen is the second most abundant gas at about 21%.
Which form of matter is known for having the property of fluidity?
Correct Answer: C. Liquids and gases
Fluids are substances that can flow and take the shape of their container, which includes both liquids and gases. They do not have a rigid shape because their particles can move past one another. Solids are not fluids because their particles are held in fixed positions.
Which of the following is a common example of a 'Sol' in colloids?
Correct Answer: D. Milk of magnesia
A 'Sol' is a colloid in which solid particles are dispersed in a liquid medium. Milk of magnesia, which is magnesium hydroxide in water, is a classic example. It is commonly used as an antacid to treat stomach acidity.
The Latin name for the element Gold is?
Correct Answer: C. Aurum
The symbol for gold is 'Au', which is derived from its Latin name 'Aurum'. 'Argentum' is the Latin name for silver, while 'Ferrum' refers to iron. Knowing Latin names helps in understanding the symbols used in the periodic table.
Which of the following is a pure element?
Correct Answer: C. Diamond
Diamond is a pure form of the element carbon arranged in a crystal structure. Steel is an alloy of iron and carbon, making it a mixture. Glass is a complex mixture of silicates and other compounds.
The zig-zag motion of colloidal particles is known as?
Correct Answer: D. Brownian motion
Brownian motion is the random movement of particles resulting from collisions with molecules of the medium. It was first observed by Robert Brown while studying pollen grains in water. This motion helps keep colloidal particles in suspension without settling.
Which of the following has the highest intermolecular space?
Correct Answer: C. Oxygen gas
The correct answer is 'Oxygen gas'. Gas particles have the largest spaces between them because of very weak attractive forces. In solids like iron or ice, particles are very closely packed. This large space explains why gases can be easily compressed.
What is the mass of one mole of water molecules?
Correct Answer: D. 18 grams
The molar mass of water (H2O) is calculated by adding the atomic masses of two hydrogen atoms and one oxygen atom. Hydrogen has a mass of 1 and oxygen has a mass of 16. Therefore, one mole of water weighs 18 grams.
Which of the following is an example of an emulsion?
Correct Answer: A. Milk
An emulsion is a colloid where both the dispersed phase and the medium are liquids. Milk is an emulsion of liquid fat globules dispersed in water. Emulsifying agents are often needed to stabilize such mixtures.