# Tag Info

14

I think to some extent, you can think about all zero-order reactions as "pseudo-zero-order" reactions. This is because it's not possible for a reaction to be true zero-order. How can it be that the rate of a reaction does not depend on any one of the reactants? So, anything that is zero-order means that there is some artifact in the system, or that ...

12

A standard example in biochemistry are enzyme-catalyzed reactions with a single substrate (e.g. ATPase, where we ignore the second substrate, water, because it is the solvent). At low substrate concentration (low reactant concentration), the reaction is first order (actually, pseudo-first order because of the water). At high susbtrate concentration (high ...

8

Zero-order kinetics can also appear in certain industrial settings. In some steel strip annealing processes where improved bendability of the product is required, steam is applied to decarburize the steel near the surfaces of the strip according to the reaction $\ce{C(s) + H2O(g) -> CO(g) +H2(g)}$ The decarburization process requires carbon to diffuse out ...

7

The best example of a zero-order reaction is the combustion of a candle. If the candle weighs $m_o$ grams at the beginning, and $m$ at any time afterwards, and if $a$ grams of it are burned per minute, the reaction rate $r$ is constant from the very beginning to the end of the candle, and it is : $r = dm/dt = a$ in grams per minute. The integrated rate law ...

5

First, be aware that the order of a chemical reaction depends on its mechanism and a great deal of chemical reactions have more than one mechanism, depending on the conditions. The traditional example for zeroth order reaction is a reaction fully dependent on a catalyst (e.g. enzymes in biochemistry). When you have enough reactants and a scarce amount of the ...

3

As it has been pointed out, molecular oxygen is paramagnetic. It is exceptional in that. Usually, you require either a transition metal ion, or a lanthanide ion, or a radical, for a molecule to be paramagnetic. For most other molecules, including as far as I can tell the fuels you mention, you can safely assume that they are diamagnetic. Paramagnetism is ...

2

Two carbon dioxide scrubbers come to mind: lithium hydroxide and soda-lime. (https://en.wikipedia.org/wiki/Lithium_hydroxide)"Lithium hydroxide is used in breathing gas purification systems for spacecraft, submarines, and rebreathers to remove carbon dioxide from exhaled gas by producing lithium carbonate and water: 2 LiOH•H2O + CO2 → Li2CO3 + 3 H2O or ...

2

How high atomic number can go is a nuclear question. Any lump of positively-charged matter will find and bind as many electrons as it needs. While it is true that the limiting value of Z is unknown an unpredictable, the same is not true for an outer boundary to the region of a (Z,N) or (Z,A) plane within which atomic nuclei can exist. Since an outer ...

1

Okay, so I managed to get a solution without too many equations by making the right approximations. First with your expressions: $\ce{K_{sp} = [Mg^2+][NH_4^+][PO_4^3-]}$ $\ce{K_{sp} = (S)(0.1)(S-x})$ Here we want to find S-x which is $\ce{[PO_4^3-]_{eq}}$. To do this, I did the following: $\ce{\frac{[PO_4^3-][H+]}{[HPO_4^2-]}=K_{a3} = 10^{-12.4}}$ Assuming \$\...

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