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Chemistry

GCSE · Edexcel

QuestionsFlashcards

Group 1
- Group 1 (Alkali Metals)
  6
- Group 1: Reactivity & Electronic Configurations
  6
Group 7
Group 0

Qualitative Analysis: Tests for Ions
Hydrocarbons
Polymers
Alcohols & Carboxylic Acids
Bulk & Surface Properties of Matter Including Nanoparticles
- Nanoparticles
  7
- Ceramics, Polymers, Composites & Metals
  5

Conservation of Mass Flashcards

All 6 cards in this deck

State the law of conservation of mass.: No atoms are lost or made in a chemical reaction, so the total mass of the products equals the total mass of the reactants.
Why does the mass not change during a precipitation reaction in a closed flask?: It is a closed system, so no substances can enter or leave; the same atoms are just rearranged.
Why does the mass decrease when a metal carbonate is heated in an open crucible?: Carbon dioxide gas is given off and escapes from the non-enclosed system.
Why does the mass increase when magnesium is burned in an open crucible?: Oxygen from the air reacts with and adds to the magnesium, and the oxide stays in the crucible.
True or false? A mass decrease in an open flask shows that mass has been destroyed.: False. Mass is conserved; a gas product has escaped into the air.
True or false? If magnesium is burned in a sealed container, the total mass stays the same.: True. Nothing can enter or leave a closed system, so the total mass is unchanged.