enthalpy

The SI unit of heat and energy is the __________.

• calorie
• heat
• joule
• watt

ΔH value in an endothermic reaction is a positive number.

• True
• False

What type of reaction is shown in the reaction pathway?

• endothermic reaction
• exothermic reaction

How do you calculate Enthalpy of a reaction?

• ΔH = ΔH_products - ΔH_reactants

• ΔT = q / mC

• ΔG = ΔH -TΔS

• E = mc²

What type of reaction is shown in the reaction pathway?

• endothermic reaction

• exothermic reaction

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

• requires energy to break

• releases energy when broken

• No energy involved

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

When new chemical bonds form, energy ____________.

• is taken into the system.

• is released from the system.

• stays the same in the system.

How much heat will be absorbed when 38.2 g of bromine reacts with excess H2 according to

the following equation?

H2 + Br2 --> 2 HBr ∆H = 72.80 kJ

• 34.8 kJ

• 17.5 kJ

• 222476.8 kJ

• 111233.4 kJ

How much heat will be transferred when 14.9 g of ammonia (NH3) reacts with excess O2 according

to the following equation? Is this reaction endothermic or exothermic?

4 NH3 + O2 --> 4 NO + 6 H2O ∆H = -1170 kJ

• -1023 kJ

• -256 kJ

• -171 kJ

• -1569 kJ