Asked in Health
What is equilibirum?
Asked in Chemistry, Elements and Compounds
How do the amounts of reactants and products change after a reaction has reached chemical equilibirum?
Asked in Badminton
What three gross motor abilities are required for badminton?
Asked in Electrical Engineering
Does inductor allows dc to pass through it?
If you took away one electron from iron what would the charge of the ion formed be?
If you assume that the iron is in equilibirum and there are initially as many protons as there are electrons, then the total charge is zero (because the protons and electrons cancel out). Now if you remove one electron (which has negative charge), you leave a net positive charge on the iron because there are more protons than there are electrons. In reality, I think electrons from other nearby iron atoms would fill the void because this "free sea of electrons" is a property of metals.
Asked in Chemistry
The correct name for an aqueous solution of H2CO3 is?
... carbonic acid Indeed, H2CO3 is called "carbonic acid." And you would think that since it is a weak acid, that there should be non-ionized molecules of H2CO3 in solution just as there are molecules of CH3COOH in a solution of ethanoic (acetic) acid. But that simply isnt the case. It has also been said that H2CO3 is an "unstable" molecule and quickly decomposes. Recent work has shown that in the absence of water, H2CO3 moleculs are quite stable. It is the pesky water moleucle that is the issue. H2CO3 molecules don't exist in aqueus solution. What we call "carbonic acid" is actually a solution of CO2 in water in equilibrium with H+ and HCO3-. CO2(aq) + H2O(l) <==> H+ + HCO3- ..... Ka is small Since the Ka for this equilibirum is small, the equilibrium lies far to the left, with CO2. Therefore, we see CO2 as the predominant species in a solution of "carbonic acid."
How does a capacitor allow ac?
A capacitor allows AC (to pass through) because capacitors resist a change in voltage. The equation of a capacitor is ... dv/dt = i/c ... meaning that the rate of change of voltage in volts per second is equal to current in amperes divided by capacitance in farads. The simplified explanation (using more words) is that, when a DC voltage is applied to a capacitor, it ultimately charges to that DC voltage and, at equilibirum, presents a large impedance, but when an AC voltage or step change is applied to a capacitor, it initially presents a low impedance, allowing the AC or step to pass through. If you have an AC signal riding on top of DC, the capacitor will stabilize to an output DC offset of zero while passing the AC. This is useful, for instance, when coupling an AC signal to the input of a transistor amplifier, while allowing the base bias circuit to keep the transistor in its intended bias state, while at the same time allowing the AC signal to pass through into the transistor and be amplified.
Asked in Economics
Is it possible for perfect competitive market to be inefficient?
It is possible for perfectly competitive markets to be inefficient when externalities are present. Externalities arise when an economic activity has an unintended impact on other economic agents and/or the market. This results in there being a socially optimal level of production that does not coincide with the privately determined equilibirum level of production derived from the supply and demand curves (which, respectively, represent the marginal private costs and marginal private benefits to producers and consumers). With respect to the efficiency of markets, positive externalities result in too little of the good in question being produced. In this case, the market equilibrium is lower than desired (the marginal social benefit curve lies above the marginal private benefit [demand] curve). In this case, the efficient market outcome would occur where the marginal social beneift curve interests the marginal private cost (supply) curve. When negative externalities occur, too much of the good in question is being produced. This results in the supply curve, which represents the marginal private costs of production, lying below the marginal social cost curve because the private cost curve fails to take into account the costs of production incurred by all of society. In this case, the efficient market outcome would occur where the marginal social cost curve coincides with the private marginal benefit (demand) curve.
Asked in Elements and Compounds
Why zinc hydroxide is soluble in excess of sodium hydroxide solution?
Zinc hydroxide Zn(OH)2 is an inorganic chemical compound. It also occurs naturally as 3 rare minerals: wülfingite (orthorhombic), ashoverite and sweetite (both tetragonal). Like the hydroxides of other metals, such as lead, aluminium, beryllium, tin and chromium, zinc hydroxide (and zinc oxide), is amphoteric. Thus it will dissolve readily in a dilute solution of a strong acid, such as HCl, and also in a solution of an alkali such as sodium hydroxide. It can be prepared by adding sodium hydroxide solution, but not in excess, to a solution of any zinc salt. A white precipitate will be seen: Zn2+ + 2OH- → Zn(OH)2. If excess sodium hydroxide is added, the precipitate of zinc hydroxide will dissolve, forming a colorless solution of zincate ion: Zn(OH)2 + 2OH- → Zn(OH)42-. This property can be used as a test for zinc ions in solution, but it is not exclusive, since aluminum and lead compounds behave in a very similar manner. Unlike the hydroxides of aluminum and lead, zinc hydroxide also dissolves in aqueous ammonia to form a colourless, water-soluble ammine complex The reason that the zinc hydroxide will dissolve is because the ion is normally surrounded by water ligands; when excess sodium hydroxide is added to the solution the hydroxide ions will reduce the complex to a -2 charge and make it soluble. When excess ammonia is added, it sets up an equilibirum which provides hydroxide ions; the formation of hydroxide ions causes a similar reaction as sodium hydroxide and creates a +2 charged complex with a co-ordination number of 4 with the ammonia ligands - this makes the complex soluble so that it dissolves
Asked in Math and Arithmetic, Chemistry, Temperature
Should the melting point and freezing point of water be the same?
At normal pressure (i.e. 1atm) water has a *freezing* point at 0'C This is the point at which its present in its solid and liquid forms at equilibirum By definition the freezing point and melting point are the same ( 0'C ) ['triple point' for water is at low pressure (611-612Pa (atm.P~101.3kPa for comparison)) and a bit above 0C (answerer mike was 'closer' on right about that one) thanks wikipedia, google, and thank God for the info they *should* be the same for water and typically 'crystalline' solids/materials like metals most of the time, many ceramics, water, etc. for more complex materials like 'polymers', there's several temperatures 'in question', *possibly* a softening pt., glass transition, (re)crystallization temp., melting pt., etc. Gof Forgive be i 'off' PLGB however, nucleating solids often requires a 'critically sized' seed crystal or an impurity or something of that sort that water 'favors' for nucleating ice, sometimes a disturbance like a vibration or something, etc. 'pure water' can be, God Willing, 'supercooled' and remain liquid for several degrees....in some metals (thanks dr. doherty and thank God) this nucleation process can often 'require', or at least be done at, several tens or maybe even hundreds of degrees 'undercooling' also, freezing pt. of water can be depressed by several impurities (thanks various and thank God), though pressure aside, only e-how thus far lists things that may raise this point. however, these actions, at least the former, change both the melting and freezing pt of water ('fusion' pt, one temp. God Willing), so 'it's all good' (i.e. putting salt down in the winter during snow or slush, when that God Willing remelts, it's hoped that the salt depresses it's freezing pt. so it doesn't freeze up easily again. thanks yahoo answers person/people who mentioned that tidbit,etc., and thanks be to GOD!)....a 'eutectic' phase diagram may 'illustrate' such schematically a bit 'better' maybe (thanks dr. doherty and thanks be to GOD indeed)