A substance has a melting point of -10°C and a boiling point of 50°C. At room temperature (25°C), it exists in which state? MCQ with Answer and Explanation
A substance has a melting point of -10°C and a boiling point of 50°C. At room temperature (25°C), it exists in which state?
A. Gas
B. Solid
C. Liquid
D. Plasma
Answer: Option C
Solution (By JKSSB Mock Tests)
Since the room temperature (25°C) is between its melting point (-10°C) and boiling point (50°C), the substance exists in the liquid state. If the temperature were below -10°C, it would be solid, and above 50°C, it would be gas. This is based on standard phase transition principles.
Explanation:
A bomb calorimeter burns a known mass of fuel in excess oxygen inside a sealed bomb immersed in water. The temperature rise of water is measured to calculate heat released. Thermometer is part of it but not the device itself.
Explanation:
Cetane number measures ignition quality of diesel fuel; higher cetane means easier ignition. Diesel has high cetane (40-55). Petrol has octane number. Methane is gas.
Explanation:
Crystallization separates a pure solid from a solution by cooling or evaporating the solvent. Impurities remain in the mother liquor. Example: purifying copper sulfate. Distillation for liquids; filtration for insoluble solids.
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