The Mole…… Thursday, Jun 21 2007 

Metals davisdag 4:07 am

We have been learning about the mole………..we know about Avogadro’s number (note that I spelt it right !! LOL) and the number of molecules in a mole. We also know how to work out the mass of one mole of substance. Guy-Lussac taught us that gases will carry out reactions in fixed, whole number ratios. This is equivalent to the numbers we use to balance an equation to show the mole ratio of the reactants and products.

So……I’ve got a question for you………… how much space does one mole of gas take up , at standard laboratory temperature and pressure?????? First in gets an award.

 

As requested……..Fridays notes Saturday, Jun 9 2007 

Metals davisdag 7:16 am

Reactivity and the periodic table.

* The most active metals are on the LHS of the periodic table, as group 1. Their reactivity increases as you move down the group.

* The next most reactive are the group 2 metals. Their reactivity also increases as you move down.

* Metals of moderate activity lie on the edge of the metal zone (such as Al, Cr, Zn, Fe, Co and Ni)

* There is no real pattern for the others, except that the least reactive are located in the lower central region of the transition netals.

The reactivity down the group in groups 1 and 2 are related to the decreasing first ionisation energies down the group. This is related to the increase in the atomic radii.

 

Writing half equations and ionic equations Thursday, Jun 7 2007 

Metals davisdag 9:49 am

without having to type equations in this post!! Arrrgggggg

Half equations help us understand the electron transfer process between metals and non-metals. Generally:

* metals lose electrons to form metal ions (cations)

* non metals gain electrons to form non-metal ions (anions)

* hydrogen ions gain electrons to form hydrogen gas.

Using these generalisations, we can write half-equations for the reactions between metals and dilute acids. Half equations must be balanced in terms of atoms and charges.

Ionic equations are created by summing two-half equations so that the number of electrons lost by the metal equals the number gained by the non-metal or hydrogen ion.

Now …….. remember the dot point for this……” construct half equations to represent the electron transfer reactions occurring when metals react with dilute hydrochloric and sulphuric acid”…..in other words you only need to be concerned with half equations associated with metals + Acid………(even though you can do it all reactions of metals 🙂  – you’re such clever chickens!!!!)

Does this help ??? Remember to use that text that holds up the leg of your desk to find some extra examples and questions to practise on………

 

Well, I’m waiting for somebody to get it right!! Saturday, Jun 2 2007 

Metals davisdag 8:11 am

Last week we partly answered my question in class. We talked about reactions with water and steam. So now you know that when a metal can react in water (only the most active will) that the products are metal hydroxide and hydrogen gas. When metals will react with steam (usually they are heated to red hot) that the products are metal oxide and hydrogen. You also learnt about writing a whole myriad of chemical reactions related to these reactions. BUT that still leaves some of the metal reactions not covered………….have we got any takers?????? I dare ya!!!!

 

Well…..here we are….first task! Tuesday, May 29 2007 

Metals davisdag 12:50 am

First quick question………reward for the class member who answers it first (correctly of course!).

We have been developing our activity series of metals……you were looking for the production of hydrogen bubbles on the surface of the metals!

Now for the quiz bit……..what are the products when a metal reacts with

a) oxygen

b) cold water

c) hot water

d) dilute HCl

e) concentrated HCl……

first in (as a comment) will get a reward…. Good Luck!