Matter & Mixtures — Set 3
Chemistry · पदार्थ और मिश्रण · Questions 21–30 of 50
Which state of matter has the highest kinetic energy of particles?
Correct Answer: A. Gas
Gas particles move rapidly and randomly, possessing the highest kinetic energy among the three common states. This high energy allows them to overcome attractive forces and fill any container. Kinetic energy increases as the temperature of the substance rises.
Tincture of iodine is a solution of iodine dissolved in?
Correct Answer: C. Alcohol
Tincture of iodine is prepared by dissolving iodine in alcohol and water. It is commonly used as an antiseptic for minor wounds and cuts. In this solution, iodine is the solute and alcohol is the solvent.
Which of the following cannot be broken down into simpler substances by chemical means?
Correct Answer: B. Oxygen
Oxygen is an element, which is the simplest form of matter that cannot be further decomposed. Compounds like water or salt can be broken down into their constituent elements. Elements are categorized as metals, non-metals, or metalloids.
What happens to the temperature during the change of state of a substance?
Correct Answer: A. It remains constant
During a phase change, the temperature remains constant because the heat energy is used to break intermolecular bonds. This heat is known as latent heat. Once the phase transition is complete, the temperature begins to change again.
Which of the following is a characteristic of a gas?
Correct Answer: B. High compressibility
Gases are highly compressible because there are large spaces between their particles. This allows a large volume of gas to be compressed into a small cylinder. Gases also lack a definite shape or volume, expanding to fill their container.
In a saltwater solution, what role does salt play?
Correct Answer: B. Solute
Salt is the solute because it is the substance being dissolved in the liquid. Water acts as the solvent because it does the dissolving and is present in a larger quantity. Together, they form a homogeneous mixture known as a solution.
Which method is used to separate components of air?
Correct Answer: A. Fractional distillation
Fractional distillation is used because the gases in the air have different boiling points. Air is first liquefied and then slowly warmed up to separate components like nitrogen and oxygen. This process is essential for industrial gas production.
Which of the following is a non-metal that is liquid at room temperature?
Correct Answer: D. Bromine
Bromine is the only non-metal that remains in a liquid state at standard room temperature. Mercury is also a liquid at room temperature, but it is a metal. Bromine is known for its reddish-brown color and pungent odor.
The purity of a substance can often be checked by measuring its?
Correct Answer: D. Melting point
Pure substances have sharp and specific melting or boiling points. Impurities usually lower the melting point or increase the boiling range of a substance. Comparing measured values to known standards helps determine the level of purity.
Which of the following is an example of a suspension?
Correct Answer: B. Chalk powder in water
Chalk powder in water is a suspension where large particles are visible to the naked eye. These particles eventually settle down at the bottom due to gravity if left undisturbed. Suspensions are heterogeneous mixtures and scatter light.