Unit 10 Review Lesson

Unit 10

Mixed Practice

Chemical Reactions:

●Result in the formation of a new substance or substances that have different properties from the reactant(s).

●Can be illustrated using a chemical equation.

●Can either gain energy or lose energy.

●Any one of the following will be present during the reaction:
○New odor formed

○Color change

○Gas produced

○Light produced

○Temperature change

○Formation of a precipitate

■Precipitate = the solid formed when 2 liquids react

Multiple Choice

Which part of the equation are the reactants?

3Ca + N₂ --> Ca₃N₂

• 3Ca

• N₂

• Ca₃N₂

• 3Ca + N₂

Multiple Choice

Which part of the eqation are the products?

2H₂O --> 2H₂ + O₂

• 2H₂O

• 2H₂

• O₂

• 2H₂ + O₂

Law of Conservation of Matter (LCM)

●Matter cannot be created or destroyed, only changed.

●LCM is why we need to balance chemical equations

●LCM is why the total mass before the reaction needs to be equal to the total
mass after the reaction

Multiple Choice

Balance this equation:

_S₂O --> _S₂ + _O₂

• 2, 2, 1

• 1, 2, 1

• 1, 1, 2

• 2, 1, 1

Multiple Choice

Balance this equation:

_N₂ + _Cl₂ --> _NCl₃

• 1, 3, 2

• 2, 1, 3

• 1, 3, 1

• 2, 3, 2

Collision Theory

●Chemical reactions happen only when the conditions are right

●Collision Theory :
○Correct orientation (favorable collision geometry)

○Sufficient kinetic energy. = Activation Energy

Reaction Rate

●Can speed up or slow down the rate of the reaction
○Temperature

○Concentration (Molarity)

○Surface Area

○Nature of reactants

○Catalyst or Inhibitor

Multiple Choice

Which of the following will speed up a reaction?

• Incease concentration

• Lower the temperature

• Add an inhibitor

• Decrease surface area

Multiple Choice

Which of the following will slow down a reaction?

• Incease concentration

• Increase the temperature

• Add an inhibitor

• Increase surface area

Potential Energy (PE) Diagram

●Shows how the energy changes as a chemical reaction takes place

●Energy lost

●Will feel warm to the touch

●Surroundings will heat up

●Have a -ΔH

●Energy gain

●Will feel cool to the touch

●Surroundings will cool down

●Have a +ΔH

Multiple Choice

An Exothermic reaction will...

• Feel warm to the touch

• Feel cool to the touch

• Have a +ΔH

• require energy

Multiple Choice

An endothermic reaction will...

• Feel warm to the touch

• Produce energy

• Have a -ΔH

• require energy

Multiple Choice

To form bonds energy is...

• released

• absorbed

• not changed