Fun Facts A
What gives evidence of a CHEMICAL change in a reaction?
Change in color, change in temperature, a distinct smell
A COMBUSTION reaction requires the presence of which element?
OXYGEN
What is the energy called that gets a chemical reaction started?
ACTIVATION ENERGY
What are the 3 parts of the collision model that must happen before reactants will react?
1. Particles must COLLIDE 2. Particles must ALIGN properly 3. Must be enough ENERGY to make it happen.
What kind of reaction is CaCO3 ->CaO + CO2
Decomposition reaction
What occurs in a REDOX reaction?
An element can lose electrons and a different element can gain electrons
What is the balanced chemical equation for Magnesium metal burning in gaseous oxygen to produce magnesium oxide?
2Mg + O2 -> 2 MgO
What happens to the energy given off in a campfire?
Some energy is absorbed by the environment, some energy is given off as light, some energy is given off as heat.
Do synthesis reactions have a SINGLE PRODUCT?
YES! For example H + O2 -> H20
Give an example of an EXOTHERMIC reaction
Gasoline burning in a car's engine
What is the GAINING of electrons called during a chemical reaction?
REDUCTION
What is an ENDOTHERMIC reaction?
A reaction that ABSORBS more energy than it releases
What is the definition of a mole?
a QUANTITY
How does a catalyst INCREASE a reaction rate?
The catalyst LOWERS the ACTIVATION energy
What happens to the FORWARD and REVERSE reactions when a system reaches its equilibrium state?
They both continue to occur at the same rate.
What kind of reaction is HCl + KOH ->H2O +KCl
Double-Replacement Reaction
Is boiling water an example of a CHEMICAL CHANGE?
No! It's an example of a PHYSICAL CHANGE
Do forces continue to act upon a system once it finally reaches equilibrium?
YES! Equilibrium goes back and forth to maintain that equilibrium.
How many moles of HYDROGEN GAS are needed for this reaction to be balanced? N2 + 3H2 -> 2NH3
3 moles of Hydrogen
What kind of reaction is NH4CL ->. <- (arrows going both directions) = NH3 + HCl
Decomposition OR Reversible reaction
What kind of reaction is N2 + 2O2 ->2NO2
Synthesis reaction
How does an increase in temperature affect REACTION RATES?
1. Particles move faster 2. This causes more collisions 3. Collisions have more energy, and reaction rate increases.
Does increasing the concentration of reactants cause a chemical reaction to speed up?
YES - concentration changes will affect the reaction rate.
What is advantageous in the scientific world - WORD equations or CHEMICAL EQUATIONS?
What is the main feature of a single-replacement reaction?
BOTH reactants and products include an element and a compound.