📚 The pH Scale: Acidity, Alkalinity and IGCSE Science | pH标度:酸性、碱性与IGCSE科学
In IGCSE Science, one of the most important concepts in chemistry is the pH scale. It tells us whether a substance is acidic, neutral or alkaline, and it has a huge impact on both chemistry and biology. In this revision guide, we will explore the key ideas you need to know for your Edexcel IGCSE exam.
在IGCSE科学中,pH标度是化学里最重要的概念之一。它告诉我们一种物质是酸性、中性还是碱性,并且对化学和生物学都有重大影响。在本复习指南中,我们将探讨你在爱德思IGCSE考试中需要掌握的核心思想。
1. What is the pH Scale? | 什么是pH标度?
The pH scale is a number scale that runs from 0 to 14. It is used to measure how acidic or alkaline a solution is.
pH标度是从0到14的数字标度,用来衡量溶液的酸性或碱性。
Acids have pH values below 7. A solution with pH 7 is neutral, and alkalis have pH values above 7.
酸的pH值低于7。pH为7的溶液呈中性,而碱的pH值高于7。
Each unit on the pH scale represents a ten-fold change in hydrogen ion concentration, although this detailed calculation is not required at IGCSE.
虽然IGCSE不要求详细计算,但pH标度上每个单位代表氢离子浓度的十倍变化。
2. Acidic, Neutral and Alkaline Solutions | 酸性、中性与碱性溶液
Acidic solutions contain an excess of hydrogen ions (H⁺). Common examples include vinegar (pH around 3) and lemon juice (pH around 2).
酸性溶液含有过量的氢离子(H⁺)。常见例子包括醋(pH约3)和柠檬汁(pH约2)。
Neutral solutions have equal concentrations of H⁺ and OH⁻ ions. Pure water is neutral with a pH of exactly 7 at 25 °C.
中性溶液中H⁺和OH⁻离子浓度相等。纯水呈中性,在25°C时pH恰好为7。
Alkaline solutions contain an excess of hydroxide ions (OH⁻). Soap and baking soda are common alkalis.
碱性溶液含有过量的氢氧根离子(OH⁻)。肥皂和小苏打是常见的碱。
You should be able to identify whether a solution is acidic, neutral or alkaline given its pH value.
你应该能够根据pH值判断溶液是酸性、中性还是碱性。
3. Why does pH Matter? | 为什么pH很重要?
pH affects many chemical reactions, biological processes, and even environmental
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