Answer:
D. Sweat evaporates from your skin
Explanation:
A physical change is a reversible process, no new substance is formed. A physical change does not affect the chemical composition of a substance.
Sweat evaporation from the skin is a physical change, because the change that occur is merely a change of state, Liquid to Gaseous state, no new substance is formed.
Single replacement reactions. For example copper is more reactive than silver. So a copper wire in a silver solution will cause the silver to become a metal again.
The ratio of effusion rates for the lightest gas H₂ to the heaviest known gas UF₆ is 13.21 to 1
<h3>What is effusion?</h3>
Effusion is a process by which a gas escapes from its container through a tiny hole into evacuated space.
Rate of effusion ∝ 1/√Ц, (where Ц is molar mass)
Rate H₂ = 1/√ЦH₂
Rate UF₆ = 1/√ЦUF₆
Therefore, Rate H₂/ Rate UF₆ = √ЦH₂/√ЦUF₆
ЦH₂= 2.016 g/mol
ЦUF₆= 352.04 g/mol
Rate H₂ / Rate UF₆ = √352.04/√2.016 = 18.76/1.42
Rate H₂ / Rate UF₆ = 13.21
Therefore, H₂ is lower mass than UF₆. Thus H₂ gas will effuse 13 times more faster than UF₆ because the most probable speed of H₂ molecule is higher; therefore, more molecules escapes per unit time.
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The nature of the Se-Cl bond in a molecule of selenium chloride (SeCl2) if the electronegativity value of selenium is 2.55 and that of chlorine is 3.16 will be MODERATELY POLAR COVALENT. Because Both of them have a very little difference in their electronegativity.