Chemistry Flashcards
Difference between hazardous and dangerous substances
Hazardous- affect human health and are assessed before experimentation
Dangerous- affect people, property and environment
Law of conservation of mass
Atoms are not lost or gained in a reaction, they are rearranged
Combustion reaction
Fuels react with oxygen to produce carbon dioxide and water
Double replacement reaction
AB+CD-> AD+CB
Single replacement reaction
A+BC->B+AC
Decomposition reaction
AB-> A+B
Synthesis reaction
A+B->AB
Neutralisation reaction
Acid+base-> water+salt (ionic substance)
When do single replacement reactions occur?
When a more reactive metal replaces a less reactive metal
What can increase the rate of a reaction?
Increase in temperature, concentration, pressure and surface area
How do catalysts increase reaction rate?
By reducing the energy required to break reactant bonds
What is the activation energy?
The minimum energy required to break reactant bonds
Ectothermic reaction
Give out energy
Endothermic
Absorb energy
Flame tests
Oxygen- reignites splint
CO2- extinguishes flame/ turns like water milky
Hydrogen- PPP
What is an acid
A molecule that is able to lose a hydrogen ion. Sour taste, corrosive, turns litmus red, pH less than 7
Bases
Able to gain hydrogen ion
Bitter taste, slippery, turns litmus blue, pH more than 7
Metallic bonding
Metals only
Ionic bonding
Metal+ non metal
Covalent bonding
Non metals only
Evidence that a reaction has occured
Formation of new products
How to calculate enthalpy
Enthalpy is the energy absorbed or released from reaction
