Answer:
Copper turns green on exposure to air
Explanation:
Liquid water freezes to form ice: Physical change
Reason: Water can melt back when it becomes ice.
Copper turns green on exposure to air: Chemical change
Reason: The copper can not change back from the green state when it turns green.
Answer:
Nacelle. The nacelle sits atop the tower and contains the gearbox, low- and high-speed shafts, generator, and brake.
Explanation:
The ph of the best buffer is 4.74
The given acetic acid is a weak acid
The equation of the pH of the buffer
pH = pKa + log ( conjugate base / weak acid ).
For best buffer the concentration of the weak acid and its conjugate base is equal.
pH = pKa + log 1
pH = pKa + 0
pH = pKa
given Ka = 1.8 × 10⁻⁵
pKa = - log ka
pH = -log ( 1.8 × 10⁻⁵ )
pH = 4. 74
Hence the pH of the best buffer is 4.74
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