Chemical Reactions and Equations

Consider the reaction that transforms one hydrogen molecule to two hydrogen atoms: H₂ ⟶ H + H. How you would describe this energy change?

• Energy is released in this reaction.

• This is an exothermic process.

• Bonds must be broken, and energy will be absorbed, making it an endothermic process.

• No energy change occurs.

Tags

NGSS.HS-PS1-4

What is the type of reaction when propane burns to yield carbon dioxide and water?

• combustion reaction

• synthesis reaction

• decomposition reaction

• redox reaction

What type of reaction is this? CH₄ + 2 O₂ --> CO₂ + 2 H₂O

• Combustion

• Synthesis

• Decomposition

• Single Replacement

Tags

NGSS.MS-PS1-2

Consider the reaction that creates one hydrogen molecule from two hydrogen atoms: H + H ⟶ H₂ How you would describe this energy change?

• Energy is absorbed in this reaction.

• This is an endothermic process.

• Bonds break in this process.

• This is an exothermic process.

Tags

NGSS.HS-PS1-4

How would you refer to the molecules on the left and right hand side of the arrow in the reaction represented: H₂ + O₂ ⟶ H₂O?

• Reactants and Products

• Substrates and Catalysts

• Reagents and Byproducts

• Inputs and Outputs

Tags

NGSS.MS-PS1-5

Why does the energy arrow go up in the reaction of ammonium nitrate and water?

• More energy was absorbed from the surroundings to break reactant bonds than was released by the formation of product bonds.

• The reaction is exothermic and releases energy.

• The temperature of the surroundings increases significantly during the reaction.

• The reaction occurs at a constant temperature without any energy change.

Tags

NGSS.HS-PS1-4

More energy was released to the surroundings by the formation of product bonds than was absorbed to break reactant bonds.

• The reaction is endothermic.

• The reaction is exothermic.

• The reaction is at equilibrium.

• The reaction is spontaneous.

Tags

NGSS.HS-PS1-4

True or False.

This is the correct, balanced equation that best represents the reaction of nitrogen with hydrogen to yield ammonia (NH₃).

N₂ + 3 H₂ --> 2 NH₃

• True.

• False.

• Not enough information.

• Only partially true.

Tags

NGSS.HS-PS1-2

What type of reaction is illustrated by the energy diagram in beaker 2?

• endothermic reaction

• exothermic reaction

• catalytic reaction

• redox reaction

Tags

NGSS.HS-PS1-4

What coefficients are needed to balance this equation? Na₂CO₃ + CaCl₂ ⟶ CaCO₃ + NaCl

• 1 before Na₂CO₃ and 1 before CaCl₂

• 1 before CaCO₃ and 1 before NaCl

• 1 before Na₂CO₃ and 2 before NaCl

• 2 before Na₂CO₃ and 1 before CaCl₂

Tags

NGSS.MS-PS1-5