Variables Impacting Effectiveness of Chemical Agents

The formula shows that
X + ZY --> ZX + Y

• X and Y bonded into a more complex molecule.
• ZY has decomposed into two smaller compounds
• X is a more reactive than Y.
• Y has changed into a new compound.

Tags

NGSS.HS-PS1-7

What type of reaction is shown below?
2KClO₃ --> 2KCl + 3 O₂ 

• Synthesis
• Decomposition
• Combustion
• Single Replacement

Based on the activity series, which metal could X represent in the reaction below?
X + Ca (NO₃)₂ -->  Ca + X (NO₃)₂

• Ba
• Fe
• Mg
• Zn

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

Which of these conditions is most likely to increase the rate of interaction among atoms and molecules?

• presence of a catalyst
• decrease in temperature
• low concentration
• increase in particle size

Tags

NGSS.HS-PS1-5

One method used to speed up the rate of a chemical reaction is to 

• add a catalyst
• add an inhibitor
• decrease the temperature
• decrease reactant concentration

Which statement defines the role of activation energy?

• Activation energy is energy that causes a reaction rate to increase.
• Activation energy is energy that causes a reaction rate to decrease.
• Activation energy is the minimum energy needed to start a reaction.
• Activation energy is the minimum energy needed for a reaction to come to completion.

Tags

NGSS.HS-PS1-5

Marsha and Nathan measure how fast an antacid tablet reacts in water at 30°C. They repeat the experiment after crushing the tablet. They conclude that the tablet produces gas bubbles much faster when it is crushed. Why does the reaction take less time when the tablet is crushed?

• increased surface area of the reactants
• decreased volume of the reactants
• increased kinetic energy of the reactants
• decreased vapor pressure of the reactants

The rate of a reaction depends on many factors such as the concentration of the reactants. Which of the following explains why an increase in the concentration of reactants affects the rate of reaction?

• The reactants move faster.
• The activation energy is lowered.
• There are fewer molecules present.
• The collisions increase between the reactants.

Tags

NGSS.HS-PS1-5

The rate at which a reaction occurs depends on the collisions between the molecules in the reactants. Which best describes the result of a temperature increase on the collisions of the molecules?

• The molecules are compressed, which decreases the number of collisions.
• The number of molecules increases, which increases the frequency of collisions.
• The molecules move faster, which increases the energy released by the collisions.
• The surface area of the molecules increases, which makes the collisions more effective.

Tags

NGSS.HS-PS1-5