🧪 Elements, Compounds & Mixtures Flashcards
(10 cards)
What’s the difference between elements, compounds, and mixtures?
Elements = one type of atom.
Compounds = chemically bonded atoms.
Mixtures = physically combined substances.
How does filtration work and when is it used?
It separates insoluble solids from liquids using filter paper.
What is simple distillation and what does it separate?
Separates solvent from a solution by evaporation and condensation.
How does chromatography help identify substances?
And how do you calculate Rf?
It separates mixtures based on solubility.
Rf value = distance moved by substance ÷ distance moved by solvent.
How can you tell if a substance is pure?
Pure substances have a fixed melting/boiling point.
Impure ones melt/boil over a range.
What are the three types of chemical bonding?
Ionic (metal + non-metal),
covalent (non-metals),
and metallic (metals).
Why do ionic compounds conduct electricity when molten?
Ions are free to move and carry charge when molten or dissolved.
What are the properties of simple molecular compounds?
Low melting/boiling points; don’t conduct electricity due to no free charges.
Why are alloys stronger than pure metals?
Different-sized atoms distort layers, making it harder for them to slide.
How do diamond and graphite differ in structure and properties?
Diamond: 4 bonds per atom, hard, no conductivity.
Graphite: 3 bonds, layers slide, conducts electricity.
