Physical & Chemical Changes; Clues to Reactions; Reaction Rates

Is making orange juice a physical or chemical change?

• Physical 
• Chemical

What makes an effective collision?

• When molecules collide.
• When molecules collide with the proper orientation.
• When molecules collide with proper orientation and enough kinetic energy.
• High Temperature.

Which of the following is NOT evidence that that a chemical reaction has occurred?

• produces light/heat
• production of a gas
• formation of a precipitate
• melting

Flammability (burns): Chemical or Physical Property

• Chemical Property
• Physical Property

What is the purpose of a catalyst?

• Helps to slow down a reaction

• Raises the activation energy

• Lowers the activation energy

• Is consumed by the reaction

A ______________ is a substance that increases the rate of a reaction without being used up during the reaction. 

• catalyst
• product
• reactant
• solute

Which of the following is true?

• The reaction rate of the diagram on the left would be greater because there are more collisions that will happen because of greater surface area.

• The reaction rate of the diagram on the right would be greater because there are more collisions that will happen because of lesser surface area.

• The reaction rate of the diagram on the right would be greater because there are more collisions that will happen because of greater surface area.

• The reaction rate of the diagram on the left would be greater because there are more collisions that will happen because of lesser surface area.

When a candle melts, it is a ___________________  change.

• chemical
• physical
• transparent
• undefined

Grinding a seltzer tablet into powder increases the rate of reaction due to increased

• concentration
• surface area
• temperature
• reactants

which factor that affect reaction rate is represented?

• Temperature

• Catalyst

• Surface Area

• Concentration