Apologia Physical Science

If you hold a container where a chemical reaction is taking place and it feels warm to you, this reaction is:

• endothermic

• exothermic

• isothermic

• what?

Tags

NGSS.HS-PS1-4

True or false: when bonds are broken the energy is positive because energy goes into the system

• True

• False

Tags

NGSS.HS-PS1-4

In the image above, this number represents the activation energy:

• 1

• 2

• 3

Tags

NGSS.HS-PS1-4

When the solids Ba(OH)₂ and NH₄SCN are mixed, a solution is produced and the temperature drops. Which statement about the energetics of this reaction is correct?

• The reaction is endothermic and ΔH is negative

• The reaction is endothermic and ΔH is positive

• The reaction is exothermic and ΔH is negative

• The reaction is exothermic and ΔH is positive

Tags

NGSS.HS-PS1-4

Does breaking bonds require energy, release energy, or not involve energy at all?

• requires energy to break

• releases energy when broken

• No energy involved

Tags

NGSS.HS-PS1-4

How can we figure out if an overall reaction is endo- or exo-thermic? It is the difference between _______ and __________.

• hot and cold temperatures

• energy to break and energy to form bonds.

• time to form a bond versus time to break a bond

Tags

NGSS.HS-PS1-4

Which bond stores the least energy per mole?

• C-H

• N-H

• H-H

• C=C

Tags

NGSS.HS-PS1-4

Which bond stores the most energy per mole?

• C-H

• N-H

• H-H

• C=C

Tags

NGSS.HS-PS1-4

The __________ law of thermodynamics states that entropy is always increasing. 

• first
• second
• third
• zeroth

Heat transfer [blank] occurs from hot to cold. 

• always
• never
• sometimes
• rarely

Tags

NGSS.HS-PS3-4