Water is an inorganic, transparent, tasteless, odorless, and nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living organisms (in which it acts as a solvent). It is vital for all known forms of life, even though it provides no calories or organic nutrients. Its chemical formula is H2O, meaning that each of its molecules contains one oxygen and two hydrogen atoms, connected by covalent bonds. Two hydrogen atoms are attached to one oxygen atom at an angle of 104.45°."Water" is the name of the liquid state of H2O at standard conditions for temperature and pressure. It forms precipitation in the form of rain and aerosols in the form of fog. Clouds consist of suspended droplets of water and ice, its solid state. When finely divided, crystalline ice may precipitate in the form of snow. The gaseous state of water is steam or water vapor.
Water covers 71% of the Earth's surface, mostly in seas and oceans. Small portions of water occur as groundwater (1.7%), in the glaciers and the ice caps of Antarctica and Greenland (1.7%), and in the air as vapor, clouds (consisting of ice and liquid water suspended in air), and precipitation (0.001%). Water moves continually through the water cycle of evaporation, transpiration (evapotranspiration), condensation, precipitation, and runoff, usually reaching the sea.
Water plays an important role in the world economy. Approximately 70% of the freshwater used by humans goes to agriculture. Fishing in salt and fresh water bodies is a major source of food for many parts of the world. Much of the long-distance trade of commodities (such as oil, natural gas, and manufactured products) is transported by boats through seas, rivers, lakes, and canals. Large quantities of water, ice, and steam are used for cooling and heating, in industry and homes. Water is an excellent solvent for a wide variety of substances both mineral and organic; as such it is widely used in industrial processes, and in cooking and washing. Water, ice and snow are also central to many sports and other forms of entertainment, such as swimming, pleasure boating, boat racing, surfing, sport fishing, diving, ice skating and skiing.
Homework Statement
A tank originally contains 100 gal of fresh water. Then water containing 1/2 lb of salt per gallon is poured into the tank at a rate of 2 gal/min, and the mixture is allowed to leave at the same rate. After 10 min the process is stopped, and fresh water is poured into the...
Hi,
I am wondering how I may calculate the rate of water flow into a container(say, a empty box) with a hole in it, and with the whole box immersed in water. Does it have something to do with the force of water pushing against the container, and calculating how fast water can flow through the...
Homework Statement
Homework EquationsThe Attempt at a Solution
I think the water waves will undergo refraction from the interface and since it is denser , it should bend towards the normal .
By that logic 4) should be correct , but this is incorrect .
I might be applying wrong concept in...
Not sure where this might best be located. This is not a question, more like a show and tell.
I read about superionic water in a NY Times article here.
Never heard of it before.
Formed at high pressure and temperature, it is described as simultaneously solid and liquid, and as "rigid lattice...
Homework Statement
Theses questions have been modified to solve my own inquiries. The originals can be found in the attached file.
A parallel plate capacitor has area A = 1 cm2, a plate separation of d = 0.01m, and is filled with air.(a) If the breakdown field is E0 = 3 × 106V/m, calculate...
Homework Statement
The apparatus shown may be used to determine the density of an unknown liquid X.
The tube has a uniform cross section and the height of the water column is twice that of Liquid X.
A and B are the same horizontal level. The pressure difference between points A and C is...
Homework Statement
Hello everybody,
How can I calculate pH value of 4.41 M HCl water solution? Is it possible for such a solution to exist?
Thank you very much for your help,
CroSinus
Homework EquationsThe Attempt at a Solution
When I try to find - log 4.41 I get a negative value. I do not...
Homework Statement
(For this problem ignore the height of the firefighter) A firefighter, a distance (d) from a building, shoots a stream of water at an initial angle, above the horizontal, at initial speed (Vo). At what height (h) does the water strike the building?
No values were given to...
Say I have a disk spinning in a buoy. Let me say the spin axis is vertical to the flat surface of the buoy (or sea if there were no waves).
Now along comes a wave (that will induce a "precession" of the disk/buoy. The axis of this precession is from "starboard to port."
This would induce...
I'm currently trying to find how much water can be condensed from an airmass of a certain dewpoint if it is sent to a lower temperature. The water will be condensed over a period of time. I have the dewpoint of the initial air and the temperature of the environment where the moist air is being...
Hi, it is well established that octanol is the preferred solvent for partition coefficient studies in environmental chemistry, however, some studies ui.e Noble A. Parition coefficients (n-octanol-water) for pesticides) J Chromat. 642 3-14, mention that estimating toxicity based on solubility in...
If water vapor is pulled inwards and cooled at a fast enough rate could if be frozen back into a solid form? i understand that they would have to be froze together as soon as contact is made but if this is possible what would the temperature have to be? And could this be the only thing that can...
Hi all,
I am new on this forum, hope you are doing good.
I have a question related to a project I am currently working on.
The system is a 40+ floors mix used building, with a cooling system composed of a couple of centrifugal chillers, and a primary/secondary pumping configuration.
There is...
Homework Statement
1. A fountain shoots water out of the ground at a 40° angle. It’s horizontal velocity is 2 m/s and the water lands 3 meters away. What is the maximum height that the water reaches during that time?
Homework Equations
Dy =vit + ½ at2
and
Vfy2 = Viy2 + 2ady
The Attempt...
Does adding oxygen influence any physical properties of water which is oxygen deficient? Is it possible that adding oxygen leads to some temperature change and expansion?
So as we know at the bottom of the ocean we have water cooled to 0-4 degrees celsius which is very dense and also compressed due to the pressure.
Imagine we lower a few kilometres long pipe to the bottom of the ocean (it's made of material that is strong enough to sustain pressure). It's closed...
Hey guys,
I have been scouring the internet to find an answer but I can not.
The problem is: I want to heat water to boiling point with the least amount of energy required. I found out that if you apply vacuum into an chamber with water (room temp), the boiling point can be as low as room...
Hello, why does the egg float upwards in a stirred bottle of water? I have tried making same experiment with other objects in different shapes but only the egg shape seems to float upwards. Here's the link to the video:
Second experiment:
Thank you for help.
Hi all this is my first post , I have been using this forum for a while , but mostly directed here by Google and have found the answers to my questions.. until now .
I am trying to design a cooling system that will use chilled water around 1deg C to cool vegetables that have been cooked.
So...
So, from my last thread “Why doesn’t the water fall out of the Earth?” I asked if the reason why water doesn’t fall out of the Earth even on its tilted axis. Then the conclusion was gravity. To be more precise, gravity is the one that pulled the water on Earth into a ball form. What in gravity...
Hello,
Is anyone familiar with the French Standard DTU for water supply infrastructure networks. I'm not understanding how to apply the diversity factors and coefficient of simultaneity to calculate the instantaneous maxumum demand and where to apply it. I was thinking of applying the formula...
Homework Statement
Question: what rate does the water lose gravitational potential energy?
Data:
I have a pipe that water is flowing through and the pipe has 2 sections.
In section 1:
- the pipe is 11.9m above section 2 so, h = 11.9m
- the velocity of water is $$v_1 = 0.3240ms^{-1}$$...
Homework Statement
Determine the factor of safety (in regard to
cohesion only) for a submerged
embankment 30.5 m (100 ft) high whose
upstream face has an inclination of 30°. The
soil properties are gtotal=18.85 kN/m3 (120
pcf), c = 37.6 kN/m2 (700 psf), f=10°
b) What is the factor of safety if...
Homework Statement
You add 1500 cal of heat to a cup of water at 22.5ºC. The water has a mass of 500.0g. What is the final temperature of the water?
Homework Equations
Q=mcΔT
The Attempt at a Solution
so i tried solving it by finding the energy of the water
Q=(500g)(1.0cal/g)(22.5ºC)
Q=11250...
Hi there. We are working on a school science project to compare how different catalysts in water splitting affect the energy/voltage needed to carry out the process. One of our catalysts will be Co-Pi, which is created by adding Cobalt-nitrate to a .1M phosphate buffer solution during...
Hello Everyone,
I've been tasked with verifying the pump external static pressure for an infrastructure water supply network. The network is a series of loops as shown in the image attached . According to the calculation notes done by the designer, the design of the network was done in watercad...
Homework Statement
I have this homework on how a Heron's fountain works. The exact assigment is as follows: "Construct a Heron's fountain and explain what (which variables) influences the height of the fountain."
I've already constructed it and it works well, but I'm not so sure about the...
OK, probably not extraterrestrial, but it did pique your interest. :)
After my dishwasher recently stopped working I learned that it has a small filter/strainer located just before the water inlet valve so I disconnected the water supply and found this slimy wormlike mass completely clogging...
Homework Statement
Homework EquationsThe Attempt at a Solution
## v = \frac { \omega } k ##
## \omega = \sqrt{ kg \tanh (k) } ##I have no idea to guess the graph.
I put g = 9.8 and tried to calculate ## \omega ## for different values of k.
## \omega (0 ) = 0,
\omega (30) =...
Hello
If I blow air containing a fixed kg/m3 of water vapour over anhydrous CaCl2, will the absorbtion rate change if the air temp is different? To simplify, we neglect exotheric heat generated by hygroscopy.
Thanks for your answers to this rather simple question.
I recently watched a great video demonstrating the floating water bridge experiment:
At around 34 sec, you can see an electrostatic discharge before the water bridge forms. I've read that this is due to the electrostatic breakdown of air between the two beakers.This made me curious about the...
He has been doing it all day, dragging, spilling, putting his paws into the water. I've tried moving the bowl to another location and changing the water but he still keeps doing this. I've managed getting him to drink a bit of water by holding the bowl myself so he wouldn't drag it across the...
[Mentor note: Thread title changed to describe actual problem being presented]
1. Homework Statement
Homework Equations
The Attempt at a Solution
I understand you have to interpolate temperature and pressure of the saturated vapor from the table, since there is no matched final specific...
Hi!
I am currently working on a project that includes rotating a water-filled container. The container is NOT spinning about its vertical axis, but about the vertical axis of the rotating disc.
I am aware that the surface shape of water in a rotating bucket takes the shape of a parabola when it...
Hi, everyone. I'm working on a personal project and I need some insight from the intelligent minds here. I'm trying to calculate the thrust that a jet motor on a marine craft needs to exert in order to accelerate the craft in a certain direction. What are the necessary factors to determine the...
Homework Statement
A person of mass M is walking across the ground carrying a heavy bucket of water of mass m on top of their head. Which of the following forces is not acting on the person?
a) The gravitational force on the person Mg acting downward
b) The normal force from the ground acting...
Falaco solitons are unique in their longevity, reportedly up to 15 minutes on the surface of a body of still water. For details and the math see {{ http://www22.pair.com/csdc/pdf/pdf/falsol.pdf }} In addition, this persistence occurs at relatively macroscopic sizes in the range of 10 to 40 cm...
A liquid in a U-tube maintains the same level in both the arms. When another liquid which does not mix with the first one is poured in it, the air interface with either of the liquids in both the arms will be at different levels.
Considering a point at the top surface of liquid A, the pressure...
So I was on my way to school this morning and looking at the beach made me think of something. Why doesn’t the water on Earth fall out and into space? Like, if you really didn’t think too hard, you’d be like, yeah, the Earth is tilted, so why, doesn’t the water fall out like a glass of water? If...
Homework Statement
n/a
Homework Equations
n/a
The Attempt at a Solution
n/a
Just a question. I keep seeing that in SN2 reactions, sometimes a molecule is quenched by H2O or H3O. I've seen it turn an O- into an OH and also a heteroatom into an H. What exactly is going on here?
Homework Statement
Lets consider a rod of length l that is attached at a point to the cealing and relvolves freely. Half of the rod is immersed in water and half of it is out of the water. The rod is not vertical it has around a 60 degree angle to the water. Where is the line of action of the...
Hello.
I have an engineering idea, an invention.
I want to make a watering valve for plants that opens the water when the soil moisture content is too low.
I am looking for a material that (1) would not rot, and (2) absorb water and contract at a significant rate to open a valve (millimeter...
I just learned that an incompressible fluid must have zero divergence within a given control volume. Given that the divergence of a fluid at a point(x,y,z) can be found by taking the scalar sum of the of the x, y, z acceleration vectors at the given point, wouldn't this mean that water flowing...
I want to remove manganese (0.7 mg/l) by aearation, from well water in an plant in which I have only chlorination sistem.Will the oxigen adition affect the action of cl2? On which point I should be careful?
I want to make oxygenation in the same tank in witch i will make the chlorination.
Would...
NASA announced in 2015 that they found some evidence for the existence of liquid water on Mars today - at least temporarily and underground.
A new study comes to a different conclusion and proposes sand as origin of the observed material transport downhill.
As interesting as these features...