Chapter 12 Flashcards
Name 5 things about physical change
- onto physical properties of a substance change
- colour, shape, size, density, mass, phase of the substance
- no changes chemically
- No new substance formed
- Electric conductivity may change
what are expansion joints?
concrete & metal expands fairly quickly so expansion joints are built into their structures to allow for this expansion
Give 2 advantages of a bi metallic strip
- ability to bend when heated
* make or break contact with another part of an electric circuit at certain temperatures functioning like a thermostat
Name four things about chemical change
- new substance formed
- chemical process that is taking take
- leads to rearrangement of atoms of the reactants to form new products
- new product may physically look different
SYNTHESIS
DECOMPOSITION
EXOTHERMIC
ENDOTHERMIC
STUDU STUDY STUDY
Name at least 3 things about explosions
- releases huge amount of energy to environment ( exothermic )
- large amount of heat energy is released & there is a rapid increase in the volume of gas products being formed
- causes pressure waves in the air
catalyst
substance which speeds up the rate of a chemical reaction without its chemical composition being changes
synthesis reaction
a chemical reaction where the product that is formed is more complex than each of the reactants
decomposition reaction
a chemical reaction where the product breaks down to form simpler substances
exothermic reaction
reactions which transform chemical potential energy into thermal energy
• release hear & increase temp •
endothermic reaction
reactions which transform thermal energy into chemical potential energy
• absorb heat & decrease temp •
The law of conservation of energy
In an isolated system energy cannot be created nor destroyed, it can only be transferred from one place to another
The law of constant proportions
Some elements in a chemical compound that bond in a fixed ratio with one another
