Chemical analysis Flashcards
What is a pure substance?
something that only contains one compound or element
How can you test the purity of a substance?
- chemically pure substance will melt or boil at a specific temperature
- measure the melting or boiling point of a sample and comparing it to that of a pure substance
- closer your measured value is to the actual melting or boiling point, the purer it is
What are formulations?
useful mixtures with a precise purpose that are made by a following ‘formula. Each component in it is present in a measured quantity, and contributes to the properties of the formulation so that it meets its required function
What is the formulation paint made of?
- pigment
- solvent
- binder
- additives
What are formulations used for?
- pharmaceutical industry- formulations of pills
- cleaning products, fuels, cosmetics, metal alloys and food and drink
What are the two different phases of chromatography?
- mobile phase- molecules can move (liquid or gas)
- stationary phase- where molecules can’t move (solid or really thick liquid)
What are some examples of greenhouse gases?
- carbon dioxide
- methane
- water vapour
Why are greenhouse gases important for the earths atmospheres?
acts as an insulating layer to allow the earth to be warm enough to support life
What is the greenhouse effect?
Greenhouse gases absorb long wavelength radiation that gets reflected back off the earth. Then they re-radiate it in all directions. As the long wavelength radiation is thermal radiation it warms the earths surface
What human activities impact the amount of greenhouse gases in the atmosphere?
- deforestation
- burning fossil fuels
- agriculture- farm animals produce methane through digestion
- creating waste
What are the consequences of climate change?
- can lead to polar ice caps melting- causing a rise in sea levels, increased flooding in coastal area and coastal erosion
- changes in rainfall patterns may cause some regions to get too much or too little water- may affect regions ability to produce food
- the frequency and severity of storms may increase
- changes in temperature and the amount of water available in a habitat may affect wild species, leading to differences in their distribution
What are carbon footprints?
a measure of the amount of carbon dioxide and other greenhouse gases released over the full life cycle of something
Why is measuring carbon footprints difficult?
because there are so many different factors to consider:
emissions from sourcing raw materials
- production of the product
- use of product
- disposal of product
Why are carbon footprints useful?
helps identify the emitters so people can avoid them in the future
What are some ways of reducing carbon footprints?
- using renewable energy sources or nuclear energy instead of fossil fuels
- Using more efficient processes could converse energy and cut waste
- government could tax companies or individuals based on the amount of greenhouse gases they emit
- Government can also put a cap on emissions of all greenhouse gases that companies make
- technology that captures CO2 produced by burning fossil fuels before it’s released into the atmosphere- stored deep underground in cracks of rocks
Why is reducing carbon footprints difficult?
- still a lot of work to be done on alternative technologies that lower CO2 emissions
- may impact the economic growth of some communities
- Not everyone is onboard so it is difficult to make international agreements
What is a ceramic?
a non-metal solid with a high melting point that aren’t made from carbon-based compounds
What are some examples of ceramics?
- clay
- glass
What are clay’s properties?
- soft material so can be moulded
-high melting point - fired at high temperatures and hardens
What is clay used to make?
pottery and bricks
What are the properties of glass?
- generally transparent
- moulded when hot
- brittle when thin
What are two types of glass?
- soda-lime glass
- borosilicate glass
How is soda-lime glass made?
heating a mixture of limestone, sand and sodium carbonate until it melts and when it cools it comes out as glass
How is borosilicate glass made?
By heating a mixture of sand and boron trioxide
