3THV - §3.1 - Characteristics of chemical reactions

• Scheikunde
• Middelbare school
• vwo
• Leerjaar 3

Reactions

you will learn

- to recognise chemical reactions.

- characteristics of a chemical reaction. 

- exothermic reactions and endothermic reactions.

- Lavoisiers's law

reaction rate

Chemical Reaction 

a reaction in which the reactants change into products.

Chemical reactions

You can recognise a chemical reaction by:

• fire
• changing colour
• smell
• sound
• light

Chemical reaction

In a chemical reaction substances disappear and new substances are formed.

reactant(s)   ---->     product(s)

What changes during a chemical reaction?

1. Nothing
2. flames
3. Fase (solid, liquid, gas)
4. characteristics of a substances

dissolving sugar

1. Chemical reaction
2. No chemical reaction

boiling an egg

1. Chemical reaction
2. No chemical reaction

boiling water

1. Chemical reaction
2. No chemical reaction

Endothermic

continuous supply of energy.

( boiling of an egg)

Exothermic

produces energy 

(combustion)

Endothermic

Exothermic

in an endothermic reaction

1. energy is released
2. only in the beginning you need energy
3. constant supply of energy

Is this reaction endothermic or exothermic?

1. exothermic
2. endothermic

Which process is exothermic?

1. baking a cake
2. melting of candle wax
3. burning of gas
4. boiling of water

Which reaction is endothermic?

1. solidification of water
2. burning of paper
3. Condensation of water
4. melting of ice

In an exothermic reaction reactants have ...........than the products

1. less energy
2. more energy
3. same energy

the law of conservation of mass, Lavoisier's law

in a chemical reaction the total mass of the reactants equals the total mass of the reaction products.

Lavoisier's law in a reactionequation

amount of atoms of each atomtype stays the same , before and after the reaction.

rate of a reaction

- Temperature

- type of substance

- Concentrattion

- surface area

- catalyst

the faster the rate of a reaction....

1. ...the longer reaction time.
2. ...the shorter reaction time

increasing concentration will ..........rate of reaction

1. increase
2. decrease
3. not change

What does not affect the reaction speed

1. Concentration
2. Time reaction takes
3. Temperature
4. Kind of substance

Reactionrate is lower at

1. more finer divided reactant
2. less finer divided reactant
3. surface area had no influence

par 3.1

questions par 3.1    

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