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