Monday, March 21, 2011

CHEMICAL FORMULA WRITING AND NAMING

Writing Chemical Formulas

1 What is the chemical formula for lead (IV) cyanide?

2 What is the chemical formula for silver chlorate?

3 What is the chemical formula for zinc carbonate?

4 What is the chemical formula for cadmium fluoride?

5 What is the chemical formula for nickel (II) sulfide?

6 What is the chemical formula for calcium oxalate?

7 What is the chemical formula for barium oxide?

8 What is the chemical formula for magnesium sulfide?

9 What is the chemical formula for pentane?

10 What is the chemical formula for lithium phosphate?

Writing Chemical Formulas

1 NaClO3 is the chemical formula for what?

2 BaS2O3 is the chemical formula for what?

3 Zn(CH3COO)2 is the chemical formula for what?

4 SrC2O4 is the chemical formula for what?

5 CuCO3 is the chemical formula for what?

6 CaS is the chemical formula for what?

7 MgO is the chemical formula for what?

8 K2CrO4 is the chemical formula for what?

9 FeF2 is the chemical formula for what?

10 KCl is the chemical formula for what?


11.
N2O5


12.
Co2O3


13.
NO2


14.
NaOH


15.
HgS


16.
NH4OH


17.
NiCl2


18.
CaCO3


19.
Ba(OH)2


20.
Cs3N


21.
AgCl


22.
NiF2


23.
N2O3


24.
AuCl3


25.
CCl4


16.
NCl3


27.
PO5


28.
CCl4


29.
Cs3PO4


30.
(NH4)2SO4

balancing chemical equation

Balancing Chemical Equations


What is a chemical equation?

When a chemical reaction occurs, it can be described by an equation. This shows the chemicals that react (called the reactants) on the left-hand side, and the chemicals that they produce (called the products) on the right-hand side. The chemicals can be represented by their names or by their chemical symbols.

Unlike mathematical equations, the two sides are separated by an arrow, that indicates that the reactants form the products and not the other way round.


The concept of balancing equations

Take a look at this chemical word equation:

Aluminium + Oxygen → Aluminium Oxide

This is the equation for the burning of aluminium in oxygen. If we convert each of the chemical names into the appropriate symbols, we get the following:

Al + O2 → Al2O3
Note that oxygen gas is diatomic, which means that the oxygen atoms, like policemen, go around in pairs. A molecule of aluminium oxide consists of two aluminium atoms combined with three oxygen atoms. Actually, technically the word "molecule" is inappropriate in that previous sentence. The formula simply tells us the ratio of aluminium atoms to oxygen atoms in the compound.

You can see by looking at it that there is something wrong with this equation. If you count the number of atoms of each type on each side, you will see that there is only one aluminium atom on the left side whereas there are two on the right. There are two oxygen atoms on the left side, as compared to three on the right side. This clearly doesn't match.

Left side: Aluminium atom Oxygen atomOxygen atom Right side: Aluminium atomAluminium atomOxygen atomOxygen atomOxygen atom

We can balance the equation by mutiplying the different atoms and molecules on each side by different amounts. Firstly, multiply the aluminium atoms on the left side by 2:

2 Al + O2 → Al2O3
Left side: Aluminium atom Aluminium atom Oxygen atomOxygen atom Right side: Aluminium atomAluminium atomOxygen atomOxygen atomOxygen atom

Now there are the same number of aluminium atoms on each side of the equation. We could also multiply the number of oxygen molecules on each side by one and a half (1.5), which would give three oxygen atoms on the left side (1.5 x 2 = 3) to match the three oxygen atoms on the right side:

2 Al + 1.5 O2 → Al2O3
Left side: Aluminium atom Aluminium atom Oxygen atomOxygen atom Oxygen atom Right side: Aluminium atomAluminium atomOxygen atomOxygen atomOxygen atom

This is now balanced, but that 1.5 is a horrible thing to have in an equation - how can you have one and a half molecules? We can solve this problem by multiplying everything throughout by 2:

4 Al + 3 O22 Al2O3
Left side: Aluminium atom Aluminium atom Oxygen atomOxygen atom Oxygen atomOxygen atom Right side: Aluminium atomAluminium atomOxygen atomOxygen atomOxygen atom

Aluminium atom Aluminium atom Oxygen atomOxygen atom
Aluminium atomAluminium atomOxygen atomOxygen atomOxygen atom
If you count the number of atoms on each side, you will find that there are four aluminium atoms on each side and six oxygen atoms.

Write your answers in the boxes. Every box will require a coefficient.

1. H2 + O2 H2O

2. H2 + N2 NH3

3. Al2O3 Al + O2

4. KClO3 KCl + O2

5. S8 + O2 SO2

6. C2H6 + O2 CO2 + H2O

7. Al2(SO4)3 + Ca(OH)2 Al(OH)3 + CaSO4

8. P4 + O2 P2O5

9. Ag + S8 Ag2S

10. Al + Br2 AlBr3

11. Cr + O2 Cr2O3

12. NaClO3 NaCl + O2

13. AlBr3 + Cl2 AlCl3 + Br2

14. Na + H2O → NaOH + H2

15. AlI3 + HgCl2 AlCl3 + HgI2

16. Ca(OH)2 + H3PO4 Ca3(PO4)2 + H2O

17. AgNO3 + K3PO4 Ag3PO4 + KNO3

18. C3H8 + O2 CO2 + H2O

19. C2H2 + O2 CO2 + H2O

20. C6H6 + O2 CO2 + H2O

WRITE THE COMPLETE PRODUCT AND BALANCE THE EQUATION

When heated, aluminium reacts with solid copper oxide to produce copper metal and aluminium oxide:
Al + CuO Al2O3 + ___
Potassium oxide is not a stable compound. In the presence of water (or even water vapour in the air), it readily converts into potassium hydroxide:
K2O + H2O _____

When calcium chloride solution is mixed with silver nitrate solution, a thick white precipitate (solid) of silver chloride appears. This is because silver chloride is insoluble: when silver ions and chloride ions find themselves together in solution, they immediately react together to form the solid. This leaves the calcium ions and nitrate ions in solution, effectively forming calcium nitrate solution.
CaCl2 + AgNO3 AgCl + ____

Magnesium will react with phosphorus to form magnesium phosphide, a chemical widely used in industry.
Mg + P4 ____