F2 - SEM2 - Common acids and alkalis - 9.4 Corrosive nature of acids Flashcards
Why pork knuckles and ginger stew is usually cooked in clay pot rather than metal pot?
Effects of acids on metals
- Pork knuckles and ginger stew contains vinegar
- Acid in the vinegar corrode the metal pots
Effects of acids on metals
What happen when dilute acids react with metals such as zinc, magnesium and iron?
Effects of acids on metals
The acids corrode the metals - metals decrease in size, hydrogen is produced
Effects of acids on metals
What is the equation of reactions between dilute acids and metals?
Effects of acids on metals
metal + acid -> salt + hydrogen
Effects of acids on metals
What happen when dilute acids react with building materials such as marble, limestone and sandstone?
Effects of acids on building materials
the acids corrode the building materials - building materials become smaller, carbon dioxide is produced
Effects of acids on building materials
What is the chemical found in building materials such as marble, limestone and sandstone?
Effects of acids on building materials
calcium carbonate
Effects of acids on building materials
What is the equation of reactions between acids and carbonate?
Effects of acids on building materials
acids + carbonate -> salt + water + carbon dioxide
Effects of acids on building materials
What is the pH value of rainwater?
Acid rain
pH5.6
What is the pH value of rainwater when considered as acid rain?
Acid rain
pH value lower than 5.6
Acid rain
What is the cause of acid rain?
Acid rain
- buring of fossil fuels releases acidic gases - sulphur dioxide and nitrogen oxides
- acidic gases react with oxygen and water in the air to form sulphuric acids and nitric acids
- make rain more acidic
Acid rain
What are the effects of acid rain on environment and living things
Effects of acid rain on environment and living things
- corroding metal objects (e.g. car bodies and metal pipes) and building materials
- killing living things in water
- damaging plants
Effects of acid rain on environment and living things
Explain why acid rain kill the livings in water?
Effects of acid rain on environment and living things
- increase acidity of the water in rivers and lakes - living things in water cannot reproduce or even die
- dissolve toxic material in soil and carry them to river
Effects of acid rain on environment and living things
Explain why acid rain damage plants?
Effects of acid rain on environment and living things
- make soil acidic - many plants cannot grow in too acidic soil
- damage the leaves - plants cannot carry out photosynthesis
- dissolve necessary for plant growth minerals in the soil and wash them away - plants become weak or die
Effects of acid rain on environment and living things
