Energy Changes in Chemistry Flashcards
Observations for burning magnesium
- grey solid burns with bright white light
- white ash is formed
Observations for heating hydrated CuSO4
- blue crystals turn white
- steam/ condensation/ colourless liquid forms
Observations for adding water to anhydrous CuSO4
- white powder turns blue
- heat is released
Observations for NaOH solution and FeCl2 solution
- green precipitate forms
Observations for CuCO3 and H2SO4
- bubbles/ fizzing
- green solid disappears
- blue solution is formed
- heat is released
Observations for Mg and CuSO4 solution
- grey solid disappears
- blue solution fades
What type of reaction is burning magnesium?
- burning/ combustion
- oxidation
What type of reaction is heating hydrated CuSO4?
- exothermic
- dehydration
What type of reaction is adding water to anhydrous CuSO4?
- hydration
- exothermic
What type of reaction is NaOH solution and FeCl2 solution?
- precipitation
What type of reaction is CuCO3 and H2SO4
- neutralisation
- exothermic
What type of reaction is Mg and CuSO4 solution
- exothermic
- displacement
Chemical reactions can be recognised by…
- temperature change 🌡️
- colour change 🔵➡️🟣
- gas production 💨
- precipitation formed 🧊
Precipitation
the formation of a solid in a solution during a chemical reaction
Exothermic
- gives out heat 🥵
- temperature rises/ increases ⬆️🌡️
Endothermic
- takes in heat 🥶
- temp. decreases/ falls ⬇️🌡️
Examples of EXOTHERMIC REACTIONS
- neutralisation
- displacement
- electrolysis
- combustion
- hydration of anhydrous salts
- rusting
- dehydration of hydrated salts
- thermal decomposition
Neutralisation
- exothermic reaction
2NaOH + H2SO4 —> NaSO4 + 2H2O
Displacement
- exothermic reaction
Mg + Cu(NO3)2 —> Mg(NO3)2 + Cu
Combustion
- non metals form gaseous acidic oxides - C + O -> CO2
- metals form solid basic oxides - Mg + O2 -> MgO
RUST
IRON + OXYGEN + WATER -> HYDRATED IRON (II) OXIDE
Examples of ENDOTHERMIC REACTIONS
- dehydration of hydrated salts
- thermal decomposition
- electrolysis
