Chemistry Flashcards
What is a combustion reaction?
Fuel+O2–>oxide+energy
-a reaction with oxygen to produce an oxide (burning)
What is a neutralisation reaction?
Acid + base = water + salt
Combining of H and OH ions
Which compound conducts electricity?
Ionic (called electrolyte)
Combustion of a hydrocarbon
CO2+H2O
Define physical change
Changes affecting the form (shape) of the chemical substance only but not its chemical composition
Define chemical change
Any change that results in the formation of a new substance
Evidence of a chemical change
Solid precipitate forms
Heat release
Light produced
Bubbling
Evidence of a physical change
Freezing
Melting
Evaporating
Physical properties
Texture, colour, melting point, boiling point, density
Chemical properties
Toxicity, flammability, radioactivity, acidity
How do I identify an acid and a base
Acid formulas start with H and base formals end with OH
Test for CO2?
Limewater; will turn cloudy
Test for H2?
Burning splint; will pop
Test for O2?
Glowing splint: will reignite
Name the first 20 elements
Hydrogen Helium Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon Sodium Magnesium Aluminium Silicon Phosphorus Sulphur Chlorine Argon Potassium Calcium
What is the correct number of bonds that atoms normally make?
H=1 O=2 C=4
Which element is a biological molecule?
Carbon
Define isotopes
The same atom with different numbers of neutrons
Acids (8)
Sour Conductive >7 pH Releases H+ Litmus paper turns pink PHTH doesn't change BPB turns yellow Reacts with metals
Define ionic bond
The complete transfer of valence electrons; generates two oppositely charged ions
Define covalent bond
Occurs when ions share electrons
Particle theory
- Matter is composed of tiny particles called atoms
- Atoms are constantly moving
- Atoms are faster as temperature increases and vice versa
- The atom is the smallest building block
Characteristics of an incomplete combustion
- lots of soot
- small reaction
- bad smell
Characteristics of complete combustion
- hardly any soot
- loud poping noise
- blue flame
Bases (8)
Bitter Conductive >7 Releases OH- Litmus turns blue PHTH turns pink BPB turns purple Doesn't react with metals
Define pure substance, homogenous, heterogenous
Pure substance: one type of particle; gold
Homogenous: a uniform mixture; air (a mix of gases)
Heterogeneous: a mix of components that aren’t uniform; oil and water
