Boyle's law relates which two variables at constant temperature?
A. Volume and temperature
B. Number of moles and volume
C. Pressure and temperature
D. Pressure and volume
Answer: Option D
Solution (By JKExamLibrary)
Boyle's law states that at constant temperature, the volume of a given mass of gas is inversely proportional to pressure: PV = constant. So P ∝ 1/V. Charles' law relates V and T at constant P. Gay-Lussac's law relates P and T at constant V. Boyle's law is used in syringes and scuba diving. Graph of P vs V is a hyperbola; P vs 1/V is a straight line.
Explanation:
Mendeleev arranged elements in order of increasing atomic mass and grouped elements with similar chemical properties. He left gaps for undiscovered elements like eka-aluminium (gallium) and eka-silicon (germanium), predicting their properties. The modern table uses atomic number as the basis. Mendeleev's table had anomalies like placing Ar (40) before K (39) due to mass order, later resolved by atomic number concept.
Explanation:
The number of half-lives elapsed is 30 days / 10 days = 3. The fraction remaining is (1/2)ⁿ, where n is the number of half-lives. So, (1/2)³ = 1/8. After 10 days: 1/2; after 20 days: 1/4; after 30 days: 1/8 of the original amount remains.
Explanation:
Galvanization is the process of applying a protective zinc coating to iron or steel to prevent rusting. Zinc acts as a sacrificial anode (more reactive than iron), corroding in preference to the iron even if the coating is scratched. Tin coating (tin-plating) protects only if the layer remains intact.
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