[lil_happy]

1) zinc+ lead(2) nitrate yield zinc nitrate + lead
2) sodium phosphate + calcium chloride yield calcium phosphate + sodium chloride
3) aluminmum +hydrochloric acid yield aluminum chloride + hydrogen gas
4) calcium hydroxide + phosphoric acid yield calcuim phosphate + water
5) copper + sulfuric acid yield copper(2) sulfate + water + sulfyr dioxide

[rudi_in]

Thank you for posting your question to the Ask Me Help Desk.

Could you be a bit more specific and tell us exactly what it is you do not understand about these reactions?

[Evil dead]

1) zinc + lead(2) nitrate yield zinc nitrate + lead

This reaction is a simple displacement reaction with zinc being the more reactive metal. If you have a compound, added with an element that is more reactive than the primary element of the particular compound, that reactive element will displace and take the place of the former element. So in this reaction Zinc displaced Lead as it was more reactive.

Full equation: Zn (aq) + Pb(II)(NO3)2 (aq) = Zn(NO3)2 (aq) + Pb (s), The displaced element usually precipates out of the solution as a solid. BTW, the '(II)' in front of the Pb stands for it's valence. This simply means how much ions it can react with. NO3 is an ion* with a charge of '-'. 2 of these may bond with the Pb as it has 2 available spaces.

*as compounds can be referred to as ions. CO3 (carbonate ion), OH (hydroxide ion) etc etc.


2) sodium phosphate + calcium chloride yield calcium phosphate + sodium chloride

This is an ionic precipitation reaction which yeilds a salt. During the reaction, Sodium and Chloride ions are soluble in solution so they remain 'spectator' ions. The compound Calcium Phosphate is however not soluble in solution, so it precipates out to make the solution cloudy (most probably). In these kinds of reactions, the most reactice elements will react with each other to make the spectator ions, the latter will usually make an insoluable substance - use that simple analogy for future reference.

Full equation: 2NaPO3 (aq) + CaCl2 (aq) = Ca(PO3)2 (s) + 2NaCl (aq)


3) aluminmum +hydrochloric acid yield aluminum chloride + hydrogen gas

Remember this rule: Acid + Metal = Salt + Hydrogen gas.
You can research this as to why, but unless you're in A-level (which I am), you will not need to know. Anyhow, the salt is the Aluminium Chloride - remember, the halogens are salt producing elements, so if they are bonded with any other single metallic element, you can deduce that as a salt, it doesn't always have to be NaCl (table salt);)

Full equation: Al (s) + 2HCl (aq) = AlCl2 (aq) + H2 (g)


4) calcium hydroxide + phosphoric acid yield calcuim phosphate + water

This is your basic neutralisation reaction, whereby the calcium Hydroxide is a base, and the phosporic acid is an acid. These reactions will always give a salt and water.

Full equation: Ca(OH)2 + PHO3 = CaHO3 + 2H2O

^^^^^^^^^^^^^^^I'm not familiar with phosphoric acid I'm afraid, wiki the correct forumla^^^^^^^^^^^^^^^^


5) copper + sulfuric acid yield copper(2) sulfate + water + sulfyr dioxide

Sulphuric acid is a funny one as it releases sulphur dioxide also. You can use damp litmus paper to confirm that Sulphur dioxide is an acidic gas. Try to write and balance to equation yourself this time ;)

[rudi_in]

Evil Dead,

You do post some good information here but the information can be easily misunderstood by the student who is just learning it. Mainly if by chance they are trying to understand how to convert the word equations into formulas to make the chemical equations.

Full equation: 2NaPO3 (aq) + CaCl2 (aq) = Ca(PO3)2 (s) + 2NaCl (aq)

sodium phosphate would be Na3PO4 and calcium phosphate would be Ca3(PO4)2

Full equation: Al (s) + 2HCl (aq) = AlCl2 (aq) + H2 (g)

Aluminum chloride would be AlCl3

Full equation: Ca(OH)2 + PHO3 = CaHO3 + 2H2O

phosphoric acid would be H3PO4 and calcium phosphate would be Ca3(PO4)2

Full equation: Zn (aq) + Pb(II)(NO3)2 (aq) = Zn(NO3)2 (aq) + Pb (s), The displaced element usually precipates out of the solution as a solid. BTW, the '(II)' in front of the Pb stands for it's valence.

While it is true that we use roman numerals to indicate the charge of the cation, it is not written in the chemical formula - only in the name.

i.e. Pb(NO3)2 is Lead(II) Nitrate


I appreciate your comments but I just ask that we try to be as careful as possible when giving this type of information.

That is why I asked for clarification.

[Capuchin]

While it is true that we use roman numerals to indicate the charge of the cation, it is not written in the chemical formula - only in the name.

i.e. Pb(NO3)2 is Lead(II) Nitrate

Just thought I would give a reason here. Metals don't have a single valency, so on their own the species has to be defined. When in a compound they are nearly always bound to a species with a single defined valency, this means that the valency state of the metal is deducable and therefore putting it in is not necessary.

For example Copper(I) Chloride and Copper(II) Chloride are written as CuCl and CuCl2 respectively.

[Capuchin]

We suggest that you help people with their homework, and not do it for them :)

And be careful to be right!

[lil_happy]

1) zinc+ lead(2) nitrate yield zinc nitrate + lead
2) sodium phosphate + calcium chloride yield calcium phosphate + sodium chloride
3) aluminmum +hydrochloric acid yield aluminum chloride + hydrogen gas
4) calcium hydroxide + phosphoric acid yield calcuim phosphate + water
5) copper + sulfuric acid yield copper(2) sulfate + water + sulfyr dioxide

i don't understand how to balance the equation ive tried several times on my own i juss don't get it

[rudi_in]

Your first step is going to be to convert all of the chemical names to formulas.

It is critical to have the correct formulas or the equations will not balance correctly.

Once you have the formulas, you need to begin determining how many atoms of each element are present in the reactants and products.

The key is to make it so that you have the same number on both sides of the arrow.

You can only make changes by using coefficients in front of the formula.
You are not allowed to change subscripts.

I would like you to post for me everything you have done to this point and I will continue to help you from there.