Chemical Changes and Reactions — Flashcards

Answer

A chemical reaction is the process of breaking the chemical bonds of the reacting substances and making new bonds to form new substances. It changes reactants into products.

Answer

A chemical bond is the force that holds the atoms of a molecule together, as in a compound. Bonds break in reactants and new bonds form in products.

Answer

General combination reaction: A + B → AB. Two substances combine to form a single new product.

Answer

Balanced equation: N2 + 3H2 ⇌ 2NH3. Iron acts as the catalyst and molybdenum acts as a promoter. The reaction is carried out at high pressure and about 450°C to 500°C.

Answer

Balanced equation: 2KClO3(s) → 2KCl(s) + 3O2(g). Potassium chlorate normally decomposes at 700°C, but with manganese dioxide it decomposes at 300°C. MnO2 remains unaffected and acts as a positive cata…

Answer

A positive catalyst speeds up a reaction. Manganese dioxide increases the rate of decomposition of potassium chlorate and hydrogen peroxide without being changed itself.

Answer

Molybdenum is a promoter, not the main catalyst. It improves the efficiency of iron in the manufacture of ammonia.

Answer

A negative catalyst is a substance that retards a reaction. Phosphoric acid retards the decomposition of hydrogen peroxide, and alcohol decreases the rate of oxidation of chloroform.