This example is an controversial matter because melting an candle is considered as both physical change and chemical change because no new substances were made by melting an candle. The final answer is C.
A barometer is used to measure the pressure in the air, Like if there was a Storm coming the barometer can forecast (Predict) The weather in the air
Explanation:
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The pH of a solution which is 0.023 m in weak base and 0 037 m in the conjugate weak acid whose Ka= 7.1 × 10⁻⁶ is 4.93.
pH determines the amount of hydrogen and hydroxide ions in a solution. It is the negative logarithm of hydrogen ion concentration.
Given,
Ka= 7.1 × 10⁻⁶
Weak base = 0.023M
Acid = 0.037M
Using base dissociation constant, Ka we can calculate pKa by:
pKa = -log [Ka]
pKa = -log [7.1 × 10⁻⁶]
pKa = 5.15
A weak base and its conjugate acid are present in equal proportions in buffer solution. Using the Henderson-Hasselbalch equation, we can find out the pH of a buffer solution that constitutes a weak base and its conjugate acid.
Using Henderson-Hasselbalch equation,
pH = pKa + log [Weak base / acid]
pH = 5.15 + log [0.023 / 0.037]
pH = 5.15 + log[0.6]
pH = 5.15 - 0.22
pH = 4.93
Therefore, the pH of the solution is 4.93.
Learn more about pH here, brainly.com/question/22390063
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Under acidic conditions, the solution is red, and under alkaline conditions, the solution is blue. Chemical reactions other than acid-base can also cause a color change to litmus paper. For instance, chlorine gas turns blue litmus paper white – the litmus dye is bleached, because of presence of hypochlorite ions.
