THE CHEMISTRY OF FIREWORKS[4]
Colors in fireworks are usually generated by pyrotechnic stars - usually just called stars -which produce intense light when ignited. Stars contain five basic types of ingredients:
- a fuel 1. ...............
- an oxidizer - 2. ...............
- color-producing chemicals
- a binder 3. ...............
- a chlorine donor 4. ...............
Some of the more common color-producing compounds are tabulated here. The color of a compound in a firework will be the same as its color in a flame test. Not all compounds that produce a colored flame are appropriate for coloring fireworks, however. Ideal colorants will produce a 5. ...............
Colour |
Example compounds |
Red |
SrCO3 (6. ...............) LiCl (7. ...............) |
Orange | CaCl2 (8. ...............) |
Yellow | NaNO3 |
Green | BaCl2 (10. ...............) |
Blue | CuCl2 (11. ...............) at low temperature |
Indigo | CsNO3 (12. ..............) |
Violet |
KNO3 (13. ...............) RbNO3 (14. ...............) |
Gold | Charcoal, 15. ............... |
White | Titanium, aluminium, beryllium, or 16. ............... powders |
The brightest stars, often called Mag Stars, are fueled by aluminium. Magnesium is rarely used in the fireworks industry due to its 17. ............... . Often an alloy of both metals called magnalium is used.
A. which provides chlorine to strengthen the color of the flame. Sometimes the oxidizer can serve this purpose
B. a compound which produces (usually) oxygen to support the combustion of the fuel
C. which allows the star to burn
D. which holds the pellet together
E. lack of ability to form a protective oxide layer
F. pure, intense color when present in moderate concentration
G. calcium chloride
H. potassium nitrate
I. barium chloride
J. iron
K. lithium chloride
L. strontium carbonate
M. cesium nitrate
N. copper chloride
O. sodium nitrate
P. rubidium nitrate
Q. magnesium