Chemical Reactions and Equations

Flashcards covering displacement, double displacement, precipitation, and various decomposition reactions (thermal, electrolytic, and photolytic) based on the lecture transcript.

Displacement reaction

A reaction in which iron or another element has displaced or removed another element, such as copper, from its solution.

$$Fe(s) + CuSO_4(aq) \rightarrow FeSO_4(aq) + Cu(s)$$

The chemical reaction where iron reacts with copper sulphate to produce iron sulphate and copper, causing the iron nail to become brownish and the blue solution to fade.

$$Zn(s) + CuSO_4(aq) \rightarrow ZnSO_4(aq) + Cu(s)$$

A displacement reaction where zinc reacts with copper sulphate to form zinc sulphate and copper.

$$Pb(s) + CuCl_2(aq) \rightarrow PbCl_2(aq) + Cu(s)$$

A displacement reaction where lead reacts with copper chloride to form lead chloride and copper.

Reactivity of Zinc and Lead

These elements are more reactive than copper and can displace copper from its compounds.

Precipitate

A white substance which is insoluble in water formed during a chemical reaction.

Precipitation reaction

Any reaction that produces an insoluble substance known as a precipitate.

Double Displacement Reaction

A reaction involving the exchange of ions, such as the reaction between sodium sulphate and barium chloride which forms a precipitate.

$$Na_2SO_4(aq) + BaCl_2(aq) \rightarrow BaSO_4(s) + 2NaCl(aq)$$

The chemical equation for the reaction of sodium sulphate and barium chloride to form barium sulphate precipitate and sodium chloride.

Thermal Decomposition of Lead Nitrate

The reaction $2Pb(NO_3)_2(s) \xrightarrow{\text{Heat}} 2PbO(s) + 4NO_2(g) + O_2(g)$ where lead nitrate decomposes into lead oxide, nitrogen dioxide, and oxygen.

Electrolysis of water

The process of using carbon electrodes and a $6\,volt$ battery to decompose water into hydrogen and oxygen gases.

Gas Ratio in Water Decomposition

During the electrolysis of water, the volume of hydrogen gas collected is double the amount of oxygen gas, appearing in a $2:1$ ratio.

Cathode and Anode collection

In the electrolysis of water, $H_2$ gas is collected at the cathode and $O_2$ gas is collected at the anode.

Decomposition of Silver Chloride

The reaction $2AgCl(s) \xrightarrow{\text{Sunlight}} 2Ag(s) + Cl_2(g)$ where white silver chloride turns grey in sunlight.

Decomposition of Silver Bromide

The reaction $2AgBr(s) \xrightarrow{\text{Sunlight}} 2Ag(s) + Br_2(g)$, which follows the same behavior as silver chloride and is used in black and white photography.

Black and white photography

The photographic process that utilizes the decomposition reactions of silver chloride and silver bromide by sunlight.