Flash and Noise Effects

In order to produce satisfactory effects a more powerful oxidiser than potassium nitrate is used together with more calorific fuels than sulfur or charcoal. In general, for a given oxidation reaction the heat evolved depends upon the oxidiser anion in the following decreasing order. 

for a given oxidiser anion, copper salts yield more heat than lead compounds, which in turn yield more than sodium, potassium, calcium or barium compounds. In practice, copper salts are not commonly used because of the difficulty involved in their ignition. However, the choice of oxidants and fuels for pyrotechnic effects is extensive, as shown in Tables 10.3 and 10.4. 

Most flash and loud report effects are produced by using a relatively powerful oxidiser such as potassium perchlorate (which has a high 

Name Formula Molecular weight Density (gcm ) Mp ( Q ah/ (kcal mol ) Total oxygen (% wt) Available oxygen (% wt) Reaction 

Sodium perchlorate NaC104 122.45 d482 100.60 52.2 52.2 2NaC104 - 2NaCl + 4O2 

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