Chem task The Acidic Environment
CHEM RESEARCH TASK
1. INDICATORS
Identify and describe some everyday uses of indicators including the testing of soil acidity/basicity. •
Indicators are used regularly in chemical laboratories during chemical reactions. One important use is to determine the end point of a titration when an acid reacts with an alkali. The reactants and products of such a reaction are colourless so an indicator is a useful way to visually determine when the reaction is complete. Chemists also need to monitor how acidic or alkaline waste solutions from industries are before they are pumped into rivers or the sea. Regulations are strict as wastes or effluent that are too acidic or too basic can be harmful to the environment.
•
•
Many people who are not chemists use indicators for:
The water in aquariums needs to be tested. Fish are sensitive to changes in their water.
If the water becomes too alkaline or too acidic it will kill fish and plants.
The water in swimming pools needs to be tested. It needs to be kept at almost neutral to avoid skin and eye irritations. Adding pool chlorine (hypochlorite ion) is one way to control acidity and stop algae from growing.
SOIL TESTING: Soil samples need to be tested. Many plants will only tolerate a narrow range of acid/base in the soil. For example, azaleas grow best in acidic soils, where beetroot thrives in slightly alkaline soils. One way to test this is to place a thin layer of white powder, such as barium sulfate or calcium sulfate, on the top of moist soil. Then place a few drops of universal indicator on it. The powder absorbs moisture from the soil, allowing the colour of the indicator to be clearly seen.
•
2. ACIDS IN THE ATMOSPHERE
Identify natural and industrial sources of sulfur dioxide and oxides of nitrogen.
Oxides of nitrogen are: Nitrous oxide (N2O), Nitric oxide (NO) and Nitrogen dioxide (NO2)
SULFUR DIOXIDE
Natural sources: Volcanoes, geothermal hot springs
Industrial sources: Combustion
1. INDICATORS
Identify and describe some everyday uses of indicators including the testing of soil acidity/basicity. •
Indicators are used regularly in chemical laboratories during chemical reactions. One important use is to determine the end point of a titration when an acid reacts with an alkali. The reactants and products of such a reaction are colourless so an indicator is a useful way to visually determine when the reaction is complete. Chemists also need to monitor how acidic or alkaline waste solutions from industries are before they are pumped into rivers or the sea. Regulations are strict as wastes or effluent that are too acidic or too basic can be harmful to the environment.
•
•
Many people who are not chemists use indicators for:
The water in aquariums needs to be tested. Fish are sensitive to changes in their water.
If the water becomes too alkaline or too acidic it will kill fish and plants.
The water in swimming pools needs to be tested. It needs to be kept at almost neutral to avoid skin and eye irritations. Adding pool chlorine (hypochlorite ion) is one way to control acidity and stop algae from growing.
SOIL TESTING: Soil samples need to be tested. Many plants will only tolerate a narrow range of acid/base in the soil. For example, azaleas grow best in acidic soils, where beetroot thrives in slightly alkaline soils. One way to test this is to place a thin layer of white powder, such as barium sulfate or calcium sulfate, on the top of moist soil. Then place a few drops of universal indicator on it. The powder absorbs moisture from the soil, allowing the colour of the indicator to be clearly seen.
•
2. ACIDS IN THE ATMOSPHERE
Identify natural and industrial sources of sulfur dioxide and oxides of nitrogen.
Oxides of nitrogen are: Nitrous oxide (N2O), Nitric oxide (NO) and Nitrogen dioxide (NO2)
SULFUR DIOXIDE
Natural sources: Volcanoes, geothermal hot springs
Industrial sources: Combustion