Questions tagged [everyday-chemistry]

Applications of chemistry to reagents, reactions and processes of everyday life. Use this tag for question on chemistry in an out-of-laboratory/class context. DO NOT use this tag merely because the question is about simple chemistry.

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7 votes
2 answers
610 views

Ozone is above, nitrogen is below

Ozone is heavier than nitrogen. Then why is ozone in stratosphere and nitrogen in troposphere?
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231 votes
1 answer
69k views

Why can we smell copper?

If I can smell an object, it means that molecules of it are getting separated from it, so they can reach my nose. As far as I know, metals don't sublimate, especially not in room temperature. However, ...
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75 votes
5 answers
20k views

How do people know HCN smells like almonds?

I was told by my chemistry teacher that $\ce{HCN}$ smells like almonds. She then went on to tell a story about how some of her students tried to play a prank on her by pouring almond extract down the ...
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6 votes
2 answers
1k views

Scientific Reason for Salt Solution Gaining Volume

A little background to this question: my mom placed a glass with salt and enough water to just cover the salt in a room to "absorb negative energy" out of the room at her office. It obviously "worked"....
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99 votes
7 answers
309k views

Is it actually possible to dispose of a body with hydrofluoric acid?

In the TV show "Breaking Bad", Walter White frequently gets rid of people who get in his way by submerging them in a plastic container full of hydrofluoric acid. This, at least in the TV show, ...
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95 votes
7 answers
64k views

Is toothpaste solid or liquid?

My teacher didn't answer this properly: Is toothpaste solid or liquid? You can't say toothpaste is a solid because solid material have a fixed shape but toothpaste doesn't. However, you can't say ...
15 votes
1 answer
2k views

What happens during cleaning silverware?

I know two distinct recipes for cleaning silver: Put them into a pot with some club soda and a piece of aluminium foil and pour over a hot water. Gently clean silverware with a fine chalk powder (...
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12 votes
5 answers
37k views

Is it possible to separate/remove sugar from common drinks, such as juice?

Is it possible to remove sugar from a drink (for example, juice) using common household equipment?
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7 votes
1 answer
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Do chemicals have an expiry date?

A bonus question would be, if so, why? Is it because it decomposes and hence the expiry date is calculated out?
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7 votes
3 answers
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Is it known for sure that bases feel slippery because of the production of soap/surfactant?

Discussion around the question Why does bleach feel slippery? has started me thinking about the saponification explanation for the slippery feeling of basic solutions. According to Wikipedia: ...
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2 votes
4 answers
1k views

How do things glow in the dark? [closed]

What makes something glow in the dark? The only explanation that I can come up with for what makes things glow in the dark is that there is probably a chemical reaction slowly releasing the light that ...
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78 votes
6 answers
25k views

Why would breathing pure oxygen be a bad idea?

My textbook mentions that SCUBA tanks often contain a mixture of oxygen and nitrogen along with a little helium which serves as a diluent. Now as I remember it, divers take care not to surface too ...
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48 votes
8 answers
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Why is the recipe of Coca Cola still a secret?

Why is the recipe for Coca-Cola still a secret? I think that given the current state of technology, it should be proficient enough to find any of the secret ingredients in Coca Cola. Any thoughts? ...
30 votes
2 answers
4k views

Is honey really a supersaturated solution? Does heating to un-crystalize redissolve it or melt it?

In the SciShow video Honey: Bacteria's Worst Enemy after about 00:30 the narrator says: Honey is only about 17% water. Most, but not all of what remains is sugar. ...
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21 votes
3 answers
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What are the chemical reactions behind fire?

I've always wondered what the chemistry behind fire is. What are the basic chemical reactions behind a simple wood fire, and how do they manifest into this phenomenon?
20 votes
3 answers
56k views

Why there is no change in water level when salt is added?

Let us say we have one glass of water and after that when we add one or two spoon of salt then we notice that salt dissolves in it but when we measure the water level we found that there is no ...
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16 votes
1 answer
2k views

Why does paper turn yellow over time?

Yesterday I saw a bill of some book which I bought 6 months back. Then this question struck my mind: "Why does paper turn yellow over time"? I remember my teacher saying some organic compound was ...
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11 votes
4 answers
96k views

Why calcium chloride is used to melt ice over sodium chloride

I'm not quite sure I understand this. My question is: Calcium chloride is a salt used widely to melt ice on sidewalks and roads. Explain why one mole of $\ce{CaCl2}$ would be more effective than ...
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10 votes
1 answer
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Why does water volume decrease when salt is added? [duplicate]

Why does water volume decrease when salt is added? Our teacher asks us in the class but I don't find any strong reason.
6 votes
2 answers
3k views

Does adding slices of lemons to water reduce its chlorine content?

Often restaurants add slices of lemon to water. They seem to make the water taste better and perhaps reduce or at least cover up the chlorine taste. I've heard that Vitamin C tablets can be used to ...
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88 votes
5 answers
104k views

Does water really 'go bad' after a couple of days?

Among my friends it is a sort of 'common wisdom' that you should throw away water after a couple of days if it was taken from the tap and stored in a bottle outside the fridge, because it has 'gone ...
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34 votes
4 answers
14k views

Why is methanol toxic?

There are two points of view for the answer of this question: The biological view, the only one that I faced during my research, states that since it can trigger perilous conditions like metabolic ...
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22 votes
3 answers
11k views

Why does milk overflow when boiled?

I was wondering that like whenever I boil milk I just have to keep standing in front of it to make sure that I don't waste any milk but then I was wondering like Why does it even overflow ? In case of ...
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18 votes
3 answers
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Why is it considered acid rain with pH <5.6?

I recently read in a book that rain is considered acid rain if the pH falls below 5.6. However a substance is acidic when the pH is below 7; so why is the boundary for acid rain 5.6? I was thinking ...
14 votes
2 answers
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Toxicity of metallic lead (Pb)

I have some pieces of lead ($\ce{Pb}$) at home. I keep them in a box in the closet and never touch them. Can it be harmful? Should I throw them away? I would like to keep them, but I am not ...
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12 votes
3 answers
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Where do the bubbles in a glass of water come from?

This weekend I accidentally left a glass of water on my kitchen table for a few days while I was out of town. Unsurprisingly, bubbles formed on the walls. As I understand from the last time I ...
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9 votes
3 answers
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Why does hand sanitizer leave your skin feeling cool?

I noticed, and perhaps many others have too, that the application of hand sanitizer (mainly ethanol), leaves one's hands feeling rather chilly after application. What is responsible for this ...
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8 votes
1 answer
3k views

How does the Mentos-Coke explosion work?

We all might have seen this in some videos or in real life. But how exactly does this work? What is the chemical reaction involved? And why is the reaction of Mentos with Diet Coke more vigorous? ...
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7 votes
4 answers
32k views

Why do other sugars melt whereas sucrose decomposes?

Sucrose decomposes at 186 °C. It doesn’t melt but when it reaches decomposition temperature, sucrose decomposes into fructose and glucose. After cooling and hardening it is no longer sucrose. Am I ...
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7 votes
1 answer
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What is the formula of bleaching powder?

What is the structure and preparation for bleaching powder? Why there is a controversy in the formula of bleaching powder? I have encountered many forms of the formula of bleaching powder, like $\...
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6 votes
1 answer
5k views

Why does zinc sulfide glow?

Zinc sulfide is used in road signs because when light from cars hit the road signs, it glows. What actually is the reason for the glowing of road signs (actually glowing of $\ce{ZnS}$)?
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6 votes
1 answer
10k views

Full equation when using vinegar, hydrogen peroxide, and salt to etch copper

What is the full chemical equation when you use the following reactants to etch copper: vinegar / acetic acid (5%) $\ce{CH3COOH (aq)}$ hydrogen peroxide (3%) $\ce{H2O2 (aq)}$ salt $\ce{NaCl (s)}$ ...
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1 vote
1 answer
932 views

When it rains, it puddles. Spilled salt cycles between wet and dry with humidity. Is this akin to a phase change?

I have some spilled un-iodized table salt (NaCl). It is very humid where I live, and when it gets very humid for a few days, the salt absorbs so much water that it becomes a puddle of (probably) ...
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81 votes
1 answer
4k views

What causes the old book smell?

I have a collection of old books (all 80+ years old), recently, I received a British Chemistry text from 1903 (intro page below) - this being the oldest book of my collection (112 years old at the ...
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46 votes
3 answers
10k views

Why does whipped cream use nitrous oxide instead of nitrogen gas?

It seems that nitrous oxide $(\ce{N2O})$ is frequently used to create whipped cream. But why can't just regular nitrogen gas $(\ce{N2})$ be used instead?
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32 votes
4 answers
8k views

How are poisons discovered? Does someone have to die/be poisoned from it first?

How are poisons discovered? Does someone have to die/be poisoned from it first? Or are there other ways of discovering the harmfulness of a substance? Perhaps everything is tested on other animals ...
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29 votes
2 answers
4k views

How to properly store acids at home?

I bought different kinds of acid for experiments and home usage that I stored in secured containers into an IKEA cabinet. I just realized that despite the fact that all the containers are properly ...
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27 votes
3 answers
26k views

Why does ice cream make soda fizz?

I've noticed that adding a chunk of ice cream to soda makes the soda fizz slightly near the soda-ice cream interface. I thought it was a physical effect due to the temperature, but adding ice has no ...
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27 votes
2 answers
11k views

Why does bleach feel slippery?

My high-school chemistry teacher taught us the mantra "bases are slippery-soapy-slimy!" This question and this answer in Quora say this is due to saponification - conversion of lipids from the top ...
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26 votes
1 answer
915 views

Why is it that every snowflake is unique?

It's pretty hard to believe in around 4.5 billion years of this planet's existence, no snowflake pattern was repeated, and that's not including potential earth-like planets. Is there a proof to the ...
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23 votes
6 answers
39k views

Why can't rust form without water?

Shouldn't iron oxide be able to form without water? It is just iron and oxygen. I don't really understand what the dot followed by the $\ce{H2O}$ means either. I was reading on wikipedia, but I have a ...
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22 votes
4 answers
82k views

Why is salt needed when using vinegar to clean pennies?

Let's say you have a solution that is vinegar and it has salt (NaCl) dissolved in it. Then you place old dull pennies in it. Then you look at it 5 minutes later and the pennies are clean and looking ...
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18 votes
2 answers
1k views

Why do chalcogens (Group VI) stink so badly?

For more fun with Dr. Derek Lowe, see this for a primer: Things I Won't Work With - Carbon Diselenide. The short of it is that we carbon-based life forms generally like oxygen. However, move just one ...
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17 votes
1 answer
6k views

What gives fresh milk a yellow tinge?

Every now and then, when I pop over to my grandparents' house, they make sure to give me a glass (or two) full of fresh milk (or "whole milk" if you will) and then proceed to pamper me for the rest of ...
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15 votes
3 answers
3k views

Mercury metal: Not toxic?

Now I (and most of us here, I guess) have grown up around "Mercury's toxic! Avoid handling it! Do NOT screw around with this thing, if you value your life" and other equally heartening pieces of ...
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15 votes
2 answers
2k views

Le Chatelier's principle: Are there any exceptions?

The way Le Chatelier's principle is presented in most introductory chemistry books (high-school) is as though it's an indisputable law of the physical world (in the sense that we're never shown an ...
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14 votes
6 answers
52k views

Handling and storing sodium hydroxide, hydrochloric acid, hydrogen peroxide and isopropyl alcohol

I'm an electrical engineering and I hope you can give me some advice as I'm not much into chemistry. I'm trying to start making my PCB (Printed Circuit Board) at home but I'd like to have some advice ...
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13 votes
1 answer
411 views

Why are snowflakes shaped as they are?

(It was the Winterbash icon that got me thinking on this.) Snow flakes take on a variety of intricate shapes, but what processes are responsible for this? (Got the image off of Wikipedia) I mean, ...
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12 votes
4 answers
10k views

The mole is used extensively in chemistry, why not elsewhere?

In chemistry, the unit "mole" is used in many places, and is an important tool when working with quantities. I have not seen it used elsewhere--for example, we never count people or TVs with the unit....
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12 votes
1 answer
3k views

Explanation of Lemon Juice-Invisible Ink

A cute homegrown spy-trick we all know: lemon juice invisible ink. But there is no scholary article available in the internet about this phenomenon. A rough explanation I found in Scientific American:...
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