Chemical reactions Flashcards
What is a chemical reaction
Two or more substances combine or mix together to form a new substance
How do you know a chemical reaction has occurred
1) colour (change)
2) heat (gets warm or cold)
3) gas (fizz)
4) solid (precipitate)
Chemical reaction example : photosynthesis
What is the difference between reactions and products
Carbon dioxide + water = reactants
Glucose + oxygen = products
The initial starting substances on the left side are called reactants
The final substances on the right side formed after the reaction are known as products
What is the law conservation of mass
We substances can only be created from other substances
… matter cannot be created or destroyed, it’s changed from form to another
Name 3 physical reactions
1) ice melting
2) boiling water
3) cutting paper
Name 3 chemical reactions
1)Rusting
2)photosynthesis
3)milk turning sour
What are two different types of reactions
Endothermic
Exothermic
What is a exothermic reaction
-“Exo” means EXIT
-Thermic means HEAT
-exothermic reactions release or “exit” heat
- heat is given out (equipment will get hot)
Examples of exothermic reactions
Burning things - combustion
Respiration of animals
Rusting if iron (nail,gate)
What is a endothermic reaction
-“endo” means ENTER
-“thermic” mean HEAT
-endothermic reactions take in heat , heat enters
-heat is absorbed from the surrounding making equipment cold
Examples of endothermic
Cooking (heat is put in)
Melting ice (heat is taken in from surroundings)
Photosynthesis (sunlight is absorbed)
What is activation energy
Some chemical reactions need energy to active the reaction
Ex. Lighting a math , friction energy gives energy to start the reaction
