Soaps & Detergents, and Suncreen's Flashcards
Is water polar or non-polar?
Polar
Is oil polar or non-polar?
Non-polar
Why can’t water and oil mix with each other?
Polar molecules (water) and non-polar molecules (oil) don’t mix and vice versa
How does soap mix with both water and oil?
Soap will dissolve the oil, causing it to mix with the water
How does soap work?
Soap breaks down the water’s surface tension
What is surface tension?
Surface tension is a property of liquids that causes them to behave as if the surface is covered by a thin membrane
How does surface tension work?
Three steps
- Whenever the water molecules get close to eachother, they tend to pull on each other quite strongly. Additionally, the direction of this pulling force goes all around, so each water molecule is pulling on other surrounding water molecules
- However, at the water’s surface, the nearby water molecules are located below and to the sides, which causes the surface water molecules to create a really strong bond, essentially deeming it as surface tension
- As a result, drops of water tend to from spherical droplets to minimize their surface area, which becomes more pronounced when the water is on a waxy surface, such as a leaf or a freshly waxed car.
Who discovered soap?
The Romans are credited to discovering soap and its preparation
How was soap made?
Used to be made with goat fat and extracts of wood ashes (containing strong bases) to convert the fat into soap
What is the definition of soaps?
Sodium salt of a long-chain carboxylic acid
What is a carboxylic acid?
A type of organic compound where the carbon at one end of the chain has a -CO2H group on it
How do we know if a carboxylic acid is present?
“oic acid” is the suffix that tells us theres a carboxylic acid present
No carboxylic acid = Methane
Carboxylic acid present = Methanoic acid
What is the polarity of the Soap’s Tail?
Is hydrophobic, the long tail is made up of only carbon and hydrogen, which is a region that does not like to mix with water
Therefore the Tail is NON-POLAR
What is the polarity of the Soap’s Head?
Is hydrophilic, as the carboxylic acid is made up of carbon and oxygen, which likes to mix with water
Therefore the head is POLAR
What is the general polarity of SOAP?
Soap is both POLAR and NON-POLAR
The tail is NON-POLAR (made of C-H non-polar bonds)
The head is POLAR (made up of C-O polar bonds)
What is a detergent?
Is a cleansing agent that consists of a molecule that has a hydrophobic tail, and a hydrophilic head
This means that all soaps are detergents, however not all detergents are soaps (soaps are specifically defined of having the sodium carboxylate head)
What are the effects of detergents on Surface Tension?
Three step process
- Detergent molecules will disrupt the attractive forces among water molecules at the surface, and as a result, lowers surface tension
- The Nonpolar, hydrophobic tails of the detergent molecules protrude out of the water surface, thereby disassociating themselves from the water molecules
- The polar hydrophilic heads of the detergent molecules are attracted to the water molecules, and therefore remains embedded among the water molecules of the water’s surface
What are Surfactants?
Are agents (like soaps and detergents) that are able to change the surface properties of water
Also known as “surface-active agents”
What is the Detergent’s Plan of Attack?
Whenever a detergent is added to water, the surface tension is disrupted, adding more detergent will cause the detergent molecules to go further into the body of water
This raises the question “won’t the hydrophobic tails prevent this?”
The detergent molecules will form micelles to prevent the hydrophobic tails from being repeled by the water molecules
What are Micelles?
Are spherical groups of detergent molecules
What are Micelles made of?
The polar, hydrophilic heads are in contact with the polar water, while the non-polar, hydrophobic tails are hidden inside the sphere
Essentially the hydrophobic tails face inwards, while the hydrophilic heads face outwards
What is the Detergent’s five step plan of attack?
- Water’s surface tension causes it to bead on the surface of fabrics
- Adding detergent lowers the water’s surface tension which allows it to…
- Penetrate into the fabric
- The detergent molecules form micells, trapping dirt, grease, and oil particles within the hydrophobic interiors of these micelles
- The grease/dirt embedded micelles disperse throughout the bulk of the water, and are carried away by rinsing with fresh water
How do Micelles’ work?
The polar head is “happy” as it is in contact with the polar water
The nonpolar tail is “happy” because it is in contact with a nonpolar oil/grease molecule
Why is soap an anionic detergent?
The heads that stick out of the micelle are negatively charged anions, therefore soap is an anionic detergent, additionally, this results in micelles to repel each other because of like forces
What are the Green Laundry Detergents ingredients for:
Surfactants
Builders (water softeners)
Enzymes
Suspension Agents/Enzyme Stabilizers
Optical Whiteners
Fragrance
Preservatives
Surfactants: Sodium lauryl sulfate (anionic, and Laureth-6 (nonionic)
Builders (water softeners): Boric acid, sodium citrate
Enzymes: Protease, amylase, and mannanase
Suspension Agents/Enzyme Stabilizers: Glycerin, calcium chloride
Optical Whiteners: None
Fragrance: Essential oils and botanical extracts
Preservatives: Methylisothiazolinone
What is Cultural Eutrophication?
The process of nutrient enrichment which results in subsequent ecosystem degradation
As detergents enter a body of water, they can be a source of food to a variety of algae and aquatic plants, which can cause their populations to bloom
What is the five step process of Cultural Eutrophication?
- Nutrient input into a water body
- Algae at the surface of the water system feed on nutrients and flourish and block sunlight from entering ecosystem
- Eventually, the algae dies and drifts to the bottom of the water system, providing food for decomposers
- As decomposers breakdown algae, they remove oxygen (O2 from the water, limiting the amount available to fish and plants
- With a hypoxic (lack of oxygen) zone created, most plants and fish die
What is the Environmental Impact of Detergents between Aquatic, Human, and Economic?
Aquatic: Oxygen depletion, and loss/changes of biodiversity
Human: The blooming of algae and phytoplankton can release toxins in the water or be toxic themselves. Additionally, the consumption of mussels and other fish that reside in the eutrophied waters can lead to health problems
Economic: Loss in fisheries, tourism, and decreased recreation and aesthetic value
Can you still get sunburnt on windy, cloudy, or even cool days?
True or false
True
If you tan but don’t burn, you don’t need to worry
about skin damage?
True or false
False
Sun exposure is important to promote Vitamin D production?
True
What happens to all radiation emitted by the sun?
23% of it is absorbed in the atmosphere
29% is reflected
48% is absorbed at the surface
What is the wavelength of light that reaches the Earth’s surface?
Acknowledge IR, Visible, and UV
39% Visible
8% UV
53% IR
How strong is UV-A and what wavelength is it?
Is the lowest energy, and has the longest wavelength of 320-400 nm
How common is UV-A?
Reaches the Earth’s surface in the greatest quantity
How strong is UV-A regarding human exposure? And what are the three results of prolonged exposure?
Three results
Penetrates farthest into the skin
- Wrinkling
- Premature aging of skin
- Certain skin cancers
How strong is UV-B and what wavelength is it?
It has medium energy, and has a shorter wavelength of 290-320 nm
What happens to most UV-B within the stratosphere?
Most of it is absorbed by the ozone within the stratosphere
What are the acute injury’s caused by UV-B exposure?
There are four results
- Sunburn
- Associated redness (along with sunburn)
- Blistering
- Peeling
What is the result of prolonged UV-B exposure within humans?
Skin cancer
What is the benefit of absorbing UV-B
Generation of Vitamin-D
How strong is UV-C and what wavelength is it?
Has the highest energy, and has the shortest wavelength of 100-290 nm
What happens to most UV-C within the stratosphere?
Is absorbed by oxygen (major) and ozone (minor) within the stratosphere, does not reach the surface of the Earth
How is UV-C Radiation Absorbed in the Atmosphere?
UV-C is absorbed by O2 (oxygen) to break bonds
UV-C is absorbed by O3 (ozone) to break bonds
Where is ozone found in the atmosphere?
90% of ozone is found within the stratosphere
What is the ozone layer?
A specific area in the stratosphere that has maximum ozone concentrations
If we were to collect all the ozone in the ozone layer, how thick would it be when it covers the surface?
It can cover the surface with a thickness of 0.5 cm
What are the Biological Effects of UV Radiation?
Photons in the Ultraviolet region of the electromagnetic spectrum has enough energy to remove electrons from neutral molecules, leaving them positively charged
Whenever this happens within living organisms, it can disrupt cells and create the potential for genetic defects and cancer
What happens to molecules when light is absorbed?
Causes them to fall apart
Which type of UV light can sunscreen protect?
Sunscreens offer broad-spectrum protection, therefore they can protect against both UV-A and UV-B radiation
What are two types of sunscreen?
- UV absorbers
- Scattering Agents
What are UV Absorbers? (sunscreen)
And how do they work?
Are compounds that can absorb UV radiation
The compound enters an excited state, and returns to the ground state by releasing energy as heat
What are Scattering Agents? (suncreen)
And how do they work?
Zinc oxide (ZnO) or titanium oxide (TiO2) will scatter and reflect sunlight from entering the skin
What are the pros and cons of Scattering Agents?
Advantage: Provides very effective protection against UV rays
Disadvantage: The sunscreen is opaque and stays white on the skin
However modern technology have now incorporated nanoparticles of TiO2 and ZnO in sunscreens so they become colourless when absorbed on skin
What is SPF in sunscreens, and what does it do?
SPF: Sun protection factor
Measures how well the suncreen can protect against UV-B radiation
What does SPF 30 mean?
SPF 30: Reduces the amount of UV-B radiation reaching the skin by a factor of 30
Essentially, someone who wears SPF 30 sunscreen would receive the same amount of radiation after 30 minutes compared to someone wearing no sunscreen who would receive the radiation after 1 minute
Which ‘suspicious’ chemical was found in suncreen? (UV-Absorbers in particular)
And what resulted of this?
A chemical called oxybenzone, was thought to be a hormone disrupter
However, a 2017 study by the Journal of American Academy of Dermatology concluded that there is no evidence that oxybenzone is harmful
Why was Oxybenzone questioned?
It came from a study when rats were fed oxybenzone, assumingly it caused harm to the rats
Is there evidence that sunscreen causes skin cancer?
Not at all, however the speculation came from studies where individuals used sunscreen more only because they were travelling to sunnier climates and sunbathed increasingly
The increased rates of skin cancer did not come from the sunscreen, but from the increased UV exposure
Are the nanoparticles used in sunscreens with ZnO harmful?
Not at all, as the nanoparticles allows the UV-blockers to absorb into the skin than stay pasty white
Another thing to know is that the nanoparticles don’t penetrate beyond the level of the skin, meaning it can’t enter the bloodstream
Are we protected by the sun by simply using sunscreen?
Not at all, because studies suggest that individuals who use sunscreen tend to stay out in the sun for longer periods of time, increasing their risk of skin cancer
Sunscreen must be used properly and diligently
Since the 1970s, what happened to the ozone concentrations?
and what did this result?
2 results
It decreased globally, resulting in increased ground UV-B radiation by
7% in NH midlatitudes in winter and spring
4% in NH midlatitudes in summer
What happened to chlorine and bromine after the 1970s ozone reduction?
There was an increase of chlorine and bromine within the stratosphere
Which compound plays the most important role in reducing stratospheric ozone?
Chlorofluorocarbons (CFCs)
Why were chlorofluorocarbons (CFCs) invented?
Three reasons
- Were invented for the refrigeration industry, to replace the previously used ammonia (which was toxic and flammable)
- CFCs were inexpensive, nontoxic, nonflammable, nonexplosive, insoluble, and chemically unreactive under tropospheric conditions, therefore are PERFECT
- In 1931, CFC-12 was produced by the DuPont chemical manufacturer under the trade name Freon, and it alongside CFC-11 were used in household and automotive air conditioning systems
What was the lifetime of CFCs?
Three types of CFC’s
CFC-11: 45 years
CFC-12: 100 years
CFC-115: 1700 years
Once they were emitted into the atmosphere, they slowly made their way to the stratosphere
What happens to CFC in the stratosphere when exposed to far-UV radiation?
They break down in the stratosphere only in the presence of far-UV radiation
How does CFC destroy ozone, and how many times does it do this process?
Chlorine that is released from a CFC compound destroys the ozone
Within the stratosphere, this cycle repeats 1000x before the chlorine is removed entirely
What were the two alternatives to CFCs?
- Hydrochlorofluorocarbon (HCFC)
- Hydrofluorocarbon (HFC)
However neither of these are perfect
What is the Antarctic Ozone Hole?
Defined to be an area of the globe which the ozone column abundance decreases below 220 Dobson Units (DU)
What happened to the Ozone Hole between 1981 to 2000
The size of the Antarctic Ozone Hole has increased from near 0 km2 to 29.4 million km2
Does Ozone absorb all UV-B radiation?
While the ozone in the stratosphere absorbs most UV-B radiation, some still manages to make it to the surface
What happens if theres a decrease in Ozone in the stratosphere?
And what is the result of this?
There will be an increase of UV-B radiation reaching the surface
This can have a variety of effects on humans, microorganisms, animals, plants, global carbon nitrogen cycles and tropospheric ozone
How does UV-B Radiation Effect Human Skin?
There are 3 effects
- Causes sunburn, as symptoms include reddening of the skin, and blistering in severse cases. Additionally susceptibility is dependent on skin type and skin pigmentation
- Skin cancer
- Photo-aging of the skin, which is accelerated aging of the skin due to long term exposure to sunlight, these symptoms include loss of skin elasticity, wrinkles, altered pigmentation, and a decrease in collagen
How does UV-B radiation effect the Human Eyes?
There are two effects
The cornea (the part that covers the iris and the lens) is most susceptible to UV-B damage
Most common eye problem associated with UV-B exposure is photokeratitis, or snow blindness, an inflammation or reddening of the eye ball
Another eye problem associated with UV-B radiation is cataracts, which is lost of transparency of the lens
How does UV-B radiation affect the Human Immune System?
There are two effects
Because the human skin contains numerous cells to fight infections produced by the immune system
- Enhanced UV-B radiation has been linked to suppression of these cells, reducing resistance to certain tumors and infections
- Suppressed immune responses to UV-B have been reported for herpes, tuberculosis, leprosy, listeriosis, and many more
What is the Montreal Protocol?
Is an international agreement that was signed initially by 27 countries, which limited the production of CFCs and halons
Additionally, a timetable was set for their eventual phase out
When did Protocol Modifications call for a phase out?
In 1990 and 1992, a phase-out was called for CFC-11 and CFC-12 by 1996, and other CFCs and halons by 2010
How long will it take for CFCs to phase out?
The stratospheric ozone layer is not expected to recover fully until 2050 or beyond
What did Paul Newman and his colleagues create?
They created a model to investigate what the ozone layer would look like today if CFC emissions were not stopped
This is also known as the “World Avoided Simulation”
What is the Goddard Earth Observing System Chemistry-Climate Model?
An Earth system model of atmospheric circulation that accounts for variations in solar energy, atmospheric chemical reactions, temperature variations and winds
What did researchers do with the Earth Observing System Chemistry-Climate Model?
Researchers increased the emissions of CFCs and other similar compounds by 3% per year, and allowed the world to evolve from 1975 to 2065
What did the “World Avoided” model show in 2020?
Hint: Deal’s with an ozone hole
17% of all ozone is depleted globally, and an ozone hole forms each year over the Arctic
What did the “World Avoided” model show in 2040?
Hint: The UV index is included
Global ozone concentrations fell below 220 DU, which were the same levels that were currently found in the Antarctica Hole
Resultingly, the UV index in a mid-latitude city reaches 15 around noon on a clear sunny day, giving perceptible sunburn in about 10 minutes
What did the “World Avoided” model show in 2050?
Account for ozone levels in the tropics
Ozone levels within the stratosphere over the tropics collapse to near zero, in a similar process that creates the Antarctic Ozone Hole
What did the “World Avoided” model show in 2065?
Global Ozone drops to 110 DU, which is a 67% drop from the 1970s
The intensity of UV radiation at Earth’s surface doubles, skin cancer-causing radiation soars
