Chemistry help needed.
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Here's a question I did.
Which conversion is an example of oxidation?
A Carbon dioxide to carbon monoxide
B. Concentrated hydrochloric acid to chlorine
For A,
CO2 -> CO
(+4) (-4) -> (+2)(-2)
oxidation state for oxygen increases from -4 to -2. however, it loses oxygen atoms. may i know whether this is oxidation or reduction?
For B,
HCl -> Cl2
(-1)(+1) -> 0
increase in oxidation state of chlorine from +1 to 0. it also loses hydrogen atom, so it is undergoing oxidation.
What I do not understand is part A... or is there something wrong with my equation (the oxidation state,etc)?
Thanks. ^_^
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B....because it's not A. A is a reduction because CO2 loses a O atom.
Ok.....a redox reaction does not include the following: acid + base, oh shit....I forgot which are the other 3 types of reactions.
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acid + base = salt and water
acid + metal = salt and hydrogen
acid + carbonate = salt and water and carbon dixion
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Right, your qns have already been addressed by 16/f/lonely and gunner77. Ok liao? Futher qns?
A Carbon dioxide to carbon monoxide
O.S. of C is decreased from +4 (in CO2) to +2 (in CO). Hence reduction.
B. Concentrated hydrochloric acid to chlorine
O.S. of Cl is increased from -1 (in HCl) to 0 (in Cl2). Hence oxidation.
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does anyone here know if acids are organic solvents? I was wondering what would happen when copper oxide reacts with sulphuric acid. may i know if is copper oxide soluble?
and anpanman, there isn't anything wrong with the way you did the question. It was right when you find the oxidation state and compare.
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Other than the most common solvent, water; commonly used solvents are organic (carbon-containing) chemicals. That's the meaning of 'organic'.
You also appear to misunderstand the meaning of solvation and solution (which are not the same). Solvation (eg. hydration) refers to electrostatic interactions or bonds being formed between that which is dissolved, and the solvent. Eg. When a soluble ionic salt is dissolved in water, energy must first be invested to overcome the ionic attraction between the cations and anions (this energy is the lattice dissociation enthalpy), then subsequently (in the Solvation process, in this case since the solvent is water, it's a subset known as Hydration process), ion-dipole bonds are formed between the cations and the polar water molecules, and between the anions and the polar water molecules. As long as Gibbs Free Energy for the entire Solution process (the enthalpy of which is endothermic Lattice Dissociation enthalpy + exothermic Solvation enthalpy; one must also take into account entropy effects) is favourable, the solution process is feasible and will occur.
It's a common misunderstanding or misconception of 'O' level students that a piece of metal or metal oxide or metal carbonate, 'dissolves' in acid. It doesn't, of course.
What transpires, is a chemical reaction (it may or may not be redox, more on this later), in which the PRODUCTS are soluble. For instance, copper(II) oxide is NOT soluble. You do NOT write CuO(s) ---> CuO(aq). When REACTED with sulphuric acid, copper(II) oxide forms copper(II) sulphate, which is soluble. You write CuO(s) + H2SO4(aq) ---> CuSO4(aq) + H2O(l).
In the case of a reactive metal, eg. Magnesium; a redox reaction occurs in which Mg(s) is oxidized to Mg2+(aq), and protons from the acid is reduced to H2(g). The Mg2+ ions are soluble with SO4 2- ions, and you obtain MgSO4(aq).
So sulphuric acid does NOT act as a solvent (organic or otherwise), it acts as an ACID (ie. proton donor; see the 3 definitions of "acid"; Arrhenius, Bronsted-Lowry, and Lewis), to REACT with copper(II) oxide, to form soluble products.
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Originally posted by bonkysleuth:
does anyone here know if acids are organic solvents? I was wondering what would happen when copper oxide reacts with sulphuric acid. may i know if is copper oxide soluble?
and anpanman, there isn't anything wrong with the way you did the question. It was right when you find the oxidation state and compare.
Define Organic.. it'll help you to answer your first question.
I assume your 'copper oxide' is copper(II) oxide.
CuO(s) + H2SO4(aq) --> CuSO4( + H2O(l)
Copper(II) Sulphate and water is formed.
Copper(II) oxide is insoluble in water. It depend on which solvent are you talking about. -
hi would like to add on.. copper oxide is a metallic oxide .. hence it is basic. Therefore, there will be an reaction with with acid. acid + base= salt and water.