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Good question. This ion has the ability to be both a proton donor and a proton acceptor. That tells us something about how this ion is going to behave in water. If you try to lower the pH of the solution by adding more H3O+, it will react with them, and if you try to raise the pH of the solution...

No. The amount of OH- and H3O+ ions present is very small, approximately 10-7 M.L-1. These equations are describing how the pH of water will be altered by the presence of this ion (not by much it would seem, because this ion is amphiprotic) These equations are describing equilibrium.

Resonance structures in Chemistry refers to bonding electrons moving rapidly between positions of roughly equivalent potential energy. So if there are two structural isomers that differ only in the position of a double bond (as in the amide that you mentioned) then both structures are equally...

Solubility is defined as the number of grams of anhydrous substance that will dissolve in 100g of water at 25oC. You should learn these three terms that describe solubility. Soluble : at least 1 g will dissolve in 100 g of water Sparingly Soluble: at least 0.1 g will dissolve in 100g of water...

Yep, agree. Think of the lamp as if it was an electrical resistor. The power output of the lamp is equal to the product of the voltage times the current. P = V x I. Assuming the resistance R of the ionised gas in the lamp is fairly constant, then P = V2/R A small increase in the voltage will...

I agree mostly with the account given by @carrotsss which is very well done. A good description of dynamic equilibrium. However, there is one feature missing - the transport problem. The radioactive Pb2+ ions will leach out of the surface of the solid and be replaced with non-radioactive Pb2+...

When you set up a multidimension array, you have to initialise "dim" the array and define explicitly how many dimensions it will hold and what data types it will hold. Then sufficient memory will be reserved to hold this size of array. It could be a 4-dimensional array. Then you can read or...

Rule 1. All glassware has to be rinsed with de-ionised water, to make sure it is not contaminated. Rule 2. Every vessel that is volumetric, i.e. it has lines scribed on the outside, must get rinsed a second and a third time with what ever solution is going in next. That means burette and pipette...

The worst teacher shortages are in STEM subjects. The Sydney Morning Herald reported on 7th October 2021 the results of a leaked report from inside the NSW Education Department...

Unfortunately, research has shown that in New South Wales schools, 41% of Physics teachers are teaching "out-of-field", i.e. outside of their area of qualification. It is one of the worst subjects for teacher shortages. Schools can't attract properly qualified Physics teachers. The metropolitan...

Yes, that is what we believe. The negative charge density of the non-bonding electron pair at the nitrogen is strongest when the adjacent carbon is bonded to carbon or hydrogen (the electronegativity of C and H is about 2). When oxygen (electronegativity of 3.44) fills a double bond on the...

Yes, there are differences in the pH (or pKa) of aqueous solutions of the various amines, but the difference is not strong. Here is some data for a series of amines: methylamine (primary) pKa = 10.64 dimethylamine (secondary) pKa = 10.71 trimetylamine (tertiary) pKa = 9.77 As you can see...

It is also good to remember not only BF3 is a Lewis acid, but also Al3+ and Fe3+ are examples of a fairly strong Lewis acids, and pH of FeCl3(aq) is quite low. Students have been asked in the past to explain the effect of various ions on pH of water. FeCl3 is a cheap and popular additive to...

The best education will extend you out of your comfort zone, so that you can achieve things that you previously did not think possible. In this way you learn something about the potential within yourself that you did not know before. Think of learning to play a musical instrument, learning to be...

Good question. The magnetic field strength, its flux and its direction, is static. It does not vary. Remember, the equations for electromagnetic induction only refer to the rate of change of the magnitude of the B-field. Anyway, in the op above, the magnetic field vector does not change. As I...

You have to loosen up your thinking, and start to think like Einstein, who told us that mass and energy are interchangeable. Mass is stored energy. If you change the potential energy of an object, a particle, an assembly of particles, whatever, then its mass will also change. Sometimes the...

Yes, I will try to explain why this is not really a paradox. Firstly, the cylindrical magnet produces a radial and symmetrical magnetic field, and it does so whether the magnet is rotating or not. Don't get confused by Faraday's description of his imaginary "lines of magnetic flux" because...

A step function in mathematics is any function whose graph consists of a series of discontinuous steps, like steps on a ladder (Google it). In the example we are considering, there is a range of frequencies for which the photocurrent is essentially zero, then a range of frequencies for which the...

The photocurrent increases suddenly. The photocurrent is a step-wise function of frequency.

That graph is reasonably consistent with what HSC students know (or should know) about the photoelectric effect. Also take into account that these are experimental data points, and the smooth line drawn through the points is not necessarily correct. I have annotated the graph with red lines to...