Rates of Reactions

Why don't all collisions between particles cause a reaction?

• the particles also need to collide with a catalyst
• not all the particles collide with enough energy
• not all the particles collide at a high enough temperature
• the particles need to collide with each other twice

Tags

NGSS.HS-PS1-5

Why do most reactions begin with a fast rate and then get slower and slower?

• they run out of energy
• the catalyst runs out
• the concentration of reactants decreases
• the temperature decreases

Tags

NGSS.HS-PS1-5

Which of these statements about rate of reaction graphs is NOT true?

• the steeper the slope, the faster the rate of reaction
• a flat slope means there is no reaction
• the shallower the slope, the faster the reaction
• as the reaction slows, the slope gets more shallow

Tags

NGSS.HS-PS1-5

Which of these is NOT a method for measuring the rate of reaction?

• measure the change in amount of reactant A
• measure the change in amount of reactant B
• measure the amount of change in product
• measure the amount of change in the catalyst

Tags

NGSS.HS-PS1-5

Which of these will NOT speed up the rate of reaction between a strip of magnesium and hydrochloric acid?

• coil up the strip of magnesium
• cut up the strip of magnesium
• increase the concentration of the hydrocholoric acid
• increase the temperature of the hydrocholoric acid

Tags

NGSS.HS-PS1-5

Why does a higher concentration increase the rate of reaction?

• it increases the amount of reactants
• it lowers the activation energy
  
• it increases the energy of particle collisions
• it increases the frequency of particle collisions

Tags

NGSS.HS-PS1-5

Why does a higher temperature increase the rate of a reaction?

• it increases both the frequency and energy of particle collisions
• it only increases the frequency of particle collisions
• it only increases the energy of particle collisions
• it reduces the activation energy of the reaction

Tags

NGSS.HS-PS1-5

Why does breaking up a solid reactant increase the rate of reaction?

• it creates more solid
• it creates more energy
• it increases the surface area
• it increases the concentration

Tags

NGSS.HS-PS1-3

Why does a catalyst increase the rate of reaction?

• it produces extra energy for the reactants
• it increases the speed of the reactant particles
• it increases the frequency of particle collisions
• it reduces the activation energy of the reaction 

Tags

NGSS.HS-PS1-4

Which of these is NOT a benefit to using a catalyst?

• it increases the rate of reaction
• it increases the amount of product
• it can save time and money
• it can help reduce pollution