Chemistry in Everyday Life
Chemistry in Everyday Life Chemistry in Everyday Life Chemistry is a big part of your everyday life. You find chemistry in daily life in the foods you eat, the air you breathe, your soap, your emotions and literally every object you can see or touch. Here’s a look at some everyday chemistry. Elements in the Human Body Your body is made up of chemical compounds, which are combinations of elements. While you probably know your body is mostly water, which is hydrogen and oxygen. Most of the human body is made up of water, H2O, with cells consisting of 65-90% water by weight.
Therefore, it isn’t surprising that most of a human body’s mass is oxygen. Carbon, the basic unit for organic molecules, comes in second. 99% of the mass of the human body is made up of just six elements: oxygen, carbon, hydrogen, nitrogen, calcium, and phosphorus. Chemistry of Love The emotions that you feel are a result of chemical messengers, primarily neurotransmitters. Love, jealousy, envy, infatuation and infidelity all share a basis in chemistry. I don’t think there are any magic love potions that you can use to make someone fall in love, but chemistry does play an important role in how a relationship progresses.
First, there’s attraction. Nonverbal communication plays a big part in initial attraction and some of this communication may involve pheromones, a form of chemical communication. Did you know that raw lust is characterized by high levels of testosterone? The sweaty palms and pounding heart of infatuation are caused by higher than normal levels of norepinephrine. Meanwhile, the ‘high’ of being in love is due to a rush of phenyl ethylamine and dopamine. All is not lost once the honeymoon is over. Lasting love confers chemical benefits in the form of stabilized production of serotonin and oxytocin. Can infidelity be blamed on chemistry?
Perhaps in part. Researchers have found that suppression of vasopressin can cause males (voles, anyway) to abandon their love nest and seek new mates. Hey, you got to have chemistry! Why Onions Make You Cry Unless you’ve avoided cooking, you’ve probably cut up an onion and experienced the burning and tearing you get from the vapours. When you cut an onion, you break cells, releasing their contents. Amino acid sulfoxides form sulfonic acids. Enzymes that were kept separate now are free to mix with the sulfonic acids to produce propanethiol S-oxide, a volatile sulphur compound that wafts upward toward your eyes.
This gas reacts with the water in your tears to form sulphuric acid. The sulphuric acid burns, stimulating your eyes to release more tears to wash the irritant away. Cooking the onion inactivates the enzyme, so while the smell of cooked onions may be strong, it doesn’t burn your eyes. Aside from wearing safety goggles or running a fan, you can keep from crying by refrigerating your onion before cutting it (slows reactions and changes the chemistry inside the onion) or by cutting the onion under water. The sulphur-containing compounds also leave a characteristic odor on your fingers.
You may be able to remove or reduce some of the smell by wiping your fingers on a stainless steel odour eater. Why Ice Floats Can you imagine how different the world around you would be if ice sank? For one thing, lakes would freeze from the bottom. Chemistry holds the explanation for why ice floats, while most substances sink when they freeze. A substance floats if it is less dense, or has less mass per unit volume, than other components in a mixture. For example, if you toss a handful of rocks into a bucket of water, the rocks, which are dense compared to the water, will sink.
The water, which is less dense than the rocks, will float. Basically, the rocks push the water out of the way, or displace it. For an object to be able to float, it has to displace a weight of fluid equal to its own weight. Water reaches its maximum density at 4°C (40°F). As it cools further and freezes into ice, it actually becomes less dense. On the other hand, most substances are most dense in their solid (frozen) state than in their liquid state. Water is different because of hydrogen bonding.
A water molecule is made from one oxygen atom and two hydrogen atoms, strongly joined to each other with covalent bonds. Water molecules are also attracted to each other by weaker chemical bonds (hydrogen bonds) between the positively-charged hydrogen atoms and the negatively-charged oxygen atoms of neighbouring water molecules. As water cools below 4°C, the hydrogen bonds adjust to hold the negatively charged oxygen atoms apart. This produces a crystal lattice, which is commonly known as ‘ice’. Ice floats because it is about 9% less dense than liquid water.
In other words, ice takes up about 9% more space than water, so a litre of ice weighs less than 1 litre water. The heavier water displaces the lighter ice, so ice floats to the top. One consequence of this is that lakes and rivers freeze from top to bottom, allowing fish to survive even when the surface of a lake has frozen over. If ice sank, the water would be displaced to the top and exposed to the colder temperature, forcing rivers and lakes to fill with ice and freeze solid. How Soap Cleans Soap is a chemical that mankind has been making for a very long time.
You can form a crude soap by mixing ashes and animal fat. How can something so nasty actually make you cleaner? The answer has to do with the way soap interacts with oil-based grease and grime. Soaps are sodium or potassium fatty acids salts, produced from the hydrolysis of fats in a chemical reaction called saponification. Each soap molecule has a long hydrocarbon chain, sometimes called its ‘tail’, with a carboxylate ‘head’. In water, the sodium or potassium ions float free, leaving a negatively-charged head. Soap is an excellent cleanser because of its ability to act as an emulsifying agent.
An emulsifier is capable of dispersing one liquid into another immiscible liquid. This means that while oil (which attracts dirt) doesn’t naturally mix with water, soap can suspend oil/dirt in such a way that it can be removed. The organic part of a natural soap is a negatively-charged, polar molecule. Its hydrophilic (water-loving) carboxylate group (-CO2) interacts with water molecules via ion-dipole interactions and hydrogen bonding. The hydrophobic (water-fearing) part of a soap molecule, its long, nonpolar hydrocarbon chain, does not interact with water molecules.
The hydrocarbon chains are attracted to each other by dispersion forces and cluster together, forming structures called micelles. In these micelles, the carboxylate groups form a negatively-charged spherical surface, with the hydrocarbon chains inside the sphere. Because they are negatively charged, soap micelles repel each other and remain dispersed in water. Grease and oil are nonpolar and insoluble in water. When soap and soiling oils are mixed, the nonpolar hydrocarbon portion of the micelles break up the nonpolar oil molecules. A different type of micelle then forms, with nonpolar soiling olecules in the centre. Thus, grease and oil and the ‘dirt’ attached to them are caught inside the micelle and can be rinsed away. Although soaps are excellent cleansers, they do have disadvantages. As salts of weak acids, they are converted by mineral acids into free fatty acids: CH3 (CH2)16CO2-Na+ + HCl > CH3 (CH2)16CO2H + Na+ + Cl- These fatty acids are less soluble than the sodium or potassium salts and form a precipitate or soap scum. Because of this, soaps are ineffective in acidic water. Also, soaps form insoluble salts in hard water, such as water containing magnesium, calcium, or iron. CH3 (CH2)16CO2-Na+ + Mg2+ > [CH3 (CH2)16CO2-] 2Mg2+ + 2 Na+ The insoluble salts form bathtub rings, leave films that reduce hair lustre, and grey/roughen textiles after repeated washings. Synthetic detergents, however, may be soluble in both acidic and alkaline solutions and doesn’t form insoluble precipitates in hard water. But that is a different story… Does Bottled Water Go Bad? Food goes bad because of chemical reactions that occur between food molecules. Fats can become rancid. Bacteria grow that can make you sick. What about products that don’t contain fat? Can bottled water go bad?
Most bottled water has an expiration date stamped on the bottle, but does the bottled water actually go bad? If so, how long is bottled water good? Here’s the answer to this common question. Although bottled water has an expiration date, it doesn’t actually go bad. Why is there an expiration date on a product that doesn’t go bad? This is because New Jersey requires all food and beverages, including water, to carry an expiration date on its packaging. It doesn’t matter if you don’t live in New Jersey… your water may carry an expiration date anyway to make it easier to standardize packaging.
Some bottled water only carries its bottling date or a ‘best by’ date. These dates are helpful because the flavour of the water will change over time as it absorbs chemicals from its packaging. The flavour will not necessarily be bad, but it may be noticeable. Leaching of chemicals from packaging is a health concern, but as far as toxic chemicals go, you can get exposure to most of those chemicals from freshly bottled water as well as bottled water that has been on the shelf a while. A ‘plastic’ taste is not necessarily an indicator that the water is bad; absence of an unpleasant lavour does not mean the water is free from contaminants. While algae and bacteria will not grow in sealed bottled water, the situation changes once the seal has been broken. You should consume or discard water within 2 weeks after opening it. Fruits That Ruin Jell-O Jell-O is an example of a polymer that you can eat. Some natural chemicals inhibit the formation of this polymer. Simply put, they ruin Jell-O. Can you name them? If you add certain fruits to Jell-O or other gelatine desserts, the gelatine won’t set up. Here’s a look at which fruits have this effect and what happens that causes them to ruin Jell-O.
Fruits That Ruin Jell-O The fruits that ruin Jell-O contain enzymes called proteases which break the chemical bonds that try to form between chains of protein as Jell-O or other gelatine tries to gel. * pineapple – bromeliad * kiwi – actinide * figs – ficain * papaya – papain * pawpaw – papain * mango * guava * ginger root Only Fresh Fruit Causes a Problem You may have had Jell-O that contained pineapple or another of the fruits on the list. This is because the enzymes in the fruit only disrupt the gelling process if the fruits are fresh or frozen.
If the fruit is heated (e. g. , canning or cooking) then the enzymes are permanently inactivated, making the fruit perfectly fine for making Jell-O. Laundry Detergent in the Dishwasher? You can apply chemistry to decide when and where to use household chemicals. While you might think detergent is detergent, so it’s interchangeable from one application to another, there are some good reasons why laundry detergent should stay in the washing machine. Yes, you could put laundry detergent in your dishwasher. Should you? Probably not. Here’s why.
Modern laundry detergents tend not to produce mountains of bubbles, but there are other good reasons to not substitute laundry detergent for dishwashing detergent. One reason is that you likely void the warranty on the appliance if you use a product not made for dishwashers. You may be exposing yourself to toxins, too. The detergent itself may be the same from one product to the other, but laundry detergents may contain brighteners, fragrances, stain removers, and anti-soiling chemicals that you don’t really need volatilized by the heat of your dishwasher so that you breathe them.
The ingredients in laundry detergent might not rinse completely from your dishes. If you are desperate for a way to wash your dishes, you can try cleaning them in the sink using other types of soap or detergent. You could try bar soap, liquid soap, or bath gel. Shampoo might leave a residue on your dishes. Laundry detergent might leave a residue, too, but at least you would have more control over rinsing in the sink compared with the dishwasher. Baking Powder versus Baking Soda You can’t interchange these two important cooking ingredients, even though they both cause baked good to rise.
Chemistry can help you understand what makes them different (and what to do if you run out of one, but have the other in your cabinet). Both baking soda and baking powder are leavening agents, which mean they are added to baked goods before cooking to produce carbon dioxide and cause them to ‘rise’. Baking powder contains baking soda, but the two substances are used under different conditions. Baking Soda Baking soda is pure sodium. When baking soda is combined with moisture and an acidic ingredient (e. g. yogurt, chocolate, buttermilk, honey), the resulting chemical reaction produces bubbles of carbon dioxide that expand under oven temperatures, causing baked goods to rise. The reaction begins immediately upon mixing the ingredients, so you need to bake recipes which call for baking soda immediately, or else they will fall flat! Baking Powder Baking powder contains sodium bicarbonate, but it includes the acidifying agent already (cream of tartar), and also a drying agent (usually starch). Baking powder is available as single-acting baking powder and as double-acting baking powder.
Single-acting powders are activated by moisture, so you must bake recipes which include this product immediately after mixing. Double-acting powders react in two phases and can stand for a while before baking. With double-acting powder, some gas is released at room temperature when the powder is added to dough, but the majority of the gas is released after the temperature of the dough increases in the oven. How Are Recipes Determined? Some recipes call for baking soda, while others call for baking powder. Which ingredient is used depends on the other ingredients in the recipe.
The ultimate goal is to produce a tasty product with a pleasing texture. Baking soda is basic and will yield a bitter taste unless countered by the acidity of another ingredient, such as buttermilk. You’ll find baking soda in cookie recipes. Baking powder contains both an acid and a base and has an overall neutral effect in terms of taste. Recipes that call for baking powder often call for other neutral-tasting ingredients, such as milk. Baking powder is a common ingredient in cakes and biscuits. Substituting in Recipes
You can substitute baking powder in place of baking soda (you’ll need more baking powder and it may affect the taste), but you can’t use baking soda when a recipe calls for baking powder. Baking soda by itself lacks the acidity to make a cake rise. However, you can make your own baking powder if you have baking soda and cream of tartar. Simply mix two parts cream of tartar with one part baking soda. How Sunscreen Works Sunscreen uses chemistry to filter or block the sun’s harmful ultraviolet rays to protect you from sunburn, skin cancer, or both.
Do you know how sunscreen works or what an SPF rating really means? Sunscreen combines organic and inorganic chemicals to filter the light from the sun so that less of it reaches the deeper layers of your skin. Like a screen door, some light penetrates, but not as much as if the door wasn’t present. Sunblock, on the other hand, reflects or scatters the light away so that it doesn’t reach the skin at all. The reflective particles in sunblock usually consist of zinc oxide or titanium oxide. In the past, you could tell who was using a sunblock just by looking, because the sunblock whited out the skin.
Not all modern sunblock are visible because the oxide particles are smaller, though you can still find the traditional white zinc oxide. Sunscreens usually include sunblock as part of their active ingredients. What Are Sunscreens Screens The portion of the sunlight that is filtered or blocked is ultraviolet radiation. There are three regions of ultraviolet light. * UV-A penetrates deeply into the skin and can lead to cancer and premature skin aging. * UV-B is involved in tanning and burning of your skin. * UV-C is completely absorbed by the earth’s atmosphere.
The organic molecules in sunscreen absorb the ultraviolet radiation and release it as heat. * PABA (para-aminobenzoic acid) absorbs UVB * Cinnamates absorb UVB * Benzophenones absorb UVA * Anthranilates absorb UVA and UVB * Ecamsules absorb UVA What SPF Means SPF stands for Sun Protection Factor. It’s a number that you can use to help determine how long you can stay in the sun before getting sunburn. Since sunburns are caused by UV-B radiation, SPF does not indicate protection from UV-A, which can cause cancer and premature aging of the skin.
Your skin has a natural SPF, partially determined by how much melanin you have, or how darkly pigmented your skin is. The SPF is a multiplication factor. If you can stay out in the sun 15 minutes before burning, using a sunscreen with an SPF of 10 would allow you to resist the burn for 10x longer or 150 minutes. Although the SPF only applies to UV-B, the labels of most products indicate if they offer broad spectrum protection, which is some indication of whether or not they work against UV-A radiation. The particles in sunblock reflect both UV-A and UV-B.
