Vocab
One or more substance (reactants) react to form two or more new substances (products); bonds are broken
Chemical reaction or chemical change
Melting ice
Physical Change
What does an arrow represent in a chemical reaction?
Yields, or reacts
When balancing an equation, there needs to be the same number and type of _______ on each side.
atoms
In these reactions, when thermal energy is absorbed
endothermic reactions
Describing what you’re seeing in a chemical reaction using chemical formulas instead of words
Chemical equation
Burning wood
Chemical Change
2MgO is this in the equation 2Mg + O2 -> 2MgO; what you end up with
Products
Is this equation balanced? (same number and type of atoms on both sides) 2K + Br2 -> 2KBr
Yes
Some reactions require more energy to break bonds than is released when new ones are formed.
MORE ENERGY→ less energy
endergonic reactions
Matter cannot be created or destroyed
Conservation of Mass
Chopping wood
Physical Change
2Mg + O2 is this in the equation 2Mg + O2 -> 2MgO; what you are starting with
Reactants
Is this equation balanced? (same number and type of atoms on each side) FeCl3 + 3KOH -> Fe(OH)3 + 3KCl
Yes
In these reactions, less energy is required to break the original bonds than is released when new bonds form.
less energy→ MORE ENERGY
exergonic reactions
When the observable form of a substance changes but the substance itself stays the same.
Physical change
Mixing vinegar and baking soda
Chemical Change
The general form a chemical reaction is written in
__________ TO ___________
Reactant to products
Is this equation balanced? (same number and type of atoms on both sides) P4 + O2 -> P2O5
NO
When the energy given off by a reaction is primarily thermal energy, the reaction is called an exothermic reaction
Exothermic reaction
How do you know that a chemical reaction has occurred?
color change, temperature change, gas, bubbles, light, fire, etc...
Rotting banana
Chemical Change
Is the total number of atoms in 3(Na2SO4)
21
Is this equation balanced? (same number and type of atoms on both sides) 2C7H10N + 21O2 → 14CO2 + 10H2O + 2NO2
Yes
Examples of this type of reaction include:
dynamite explosion, burning fossil fuels
Exothermic Reaction