Reactions you need to know

Group 1 Elements (Alkali Metals) + Water = Metal Hydroxide + Hydrogen gas

Group 1 Elements (Alkali Metals) normally react with non-metals to form ionic compounds held together by ionic bonds

Group 1 Elements (Alkali Metals) + Chlorine = Chlorine salt

Group 7 Elements (Halogens) + Metal (normally group 1) = metalHalide (a Halide is a negative halogen ion e.g fluoride instead of fluorine) an ionic compound held together by an ionic bond

Group 0 Elements (Noble gases) = don’t react cause they have a full electron outer shell (Inert)

A displacement reaction occurs when a more reactive element displaces, or pushes out, a less reactive element from a compound that contains the less reactive element e.g magnesium + copper sulfate → copper + magnesium sulfate

A combustion reaction is when a substance reacts with oxygen and releases a huge amount of energy in the form of light and heat. A combustion reaction always includes a hydrocarbon and oxygen as the reactants and always produces carbon dioxide and water as products. Fuel(Hydrocarbon) + Oxygen → Carbon Dioxide + Water

Thermal decomposition refers a type of reaction where a single reactant is broken down into multiple products when heated. A key example is the decomposition of metal carbonates when heated, which produces the metal oxide and carbon dioxide. copper carbonate → copper oxide + carbon dioxide

Oxygen + Hydrogen = Water is the chemical reaction used to describe how hydrogen and oxygen are turned in energy and water in the form of steam.

Endothermic reactions are chemical or physical processes that absorb heat from their surroundings, causing a decrease in the temperature of the surroundings. Objects reacting endothermically feel cold because they are absorbing heat and turning it into chemical energy

Exothermic transfer energy to the surroundings causing an increase in the temperature of the surroundings. The energy is usually transferred as heat energy, causing the reaction mixture and its surroundings to become hotter.Objects reacting exothermically feel warm because they are turning their chemical energy into heat making the object feel warm

Metal + Acid = Metal Salt + Hydrogen

To test for hydrogen gas, a burning splint (a small stick of wood) is introduced to the mouth of a test tube containing the gas. If the gas is hydrogen, a "squeaky pop" sound will be heard as the hydrogen reacts with the oxygen in the air = This is because the hydrogen reacts with oxygen explosively to form water (hydrogen + oxygen = water)

Metal+oxygen = Metal oxide

When a reactive metal like sodium or calcium is placed in cold water, it reacts quickly and displaces one hydrogen molecule. The metal bonds with the hydroxide (OH⁻) part to form a metal hydroxide, and the hydrogen (H) is released as hydrogen gas. Since the water is cool, the hydroxide stays stable and dissolves in the water, making it alkaline. This kind of reaction is easy for very reactive metals because they don’t need much energy to get started. Metal+Water = Metal hydroxide + hydrogen

Less reactive metals like magnesium or iron don’t react much with cold water, but they do react with steam, which is hot water vapor. The heat gives the metal enough energy to react, forming a metal oxide and hydrogen gas instead of a hydroxide. More reactive metals like sodium and potassium can also react with steam, but they usually react even faster with cold water, so steam isn’t needed. In general, the high temperature of steam favors the formation of oxides, especially for metals that need extra energy to start reacting. Metal+Steam = Metal oxide + hydrogen

A metal displacement reaction happens when a more reactive metal is added to a compound of a less reactive metal, causing the less reactive one to be displaced. (often used in extracting ores) For example: More reactive metal + Less reactive metal compound → More reactive metal Compound + Less reactive metal Zinc + Copper sulfate → Zinc sulfate + Copper