Endo/Exothermic

Endo/Exothermic

Multiple Choice

What is the equation to measure change in Thermal Energy?

• Q=mc∆t
• Q=mc
• Q= ∆mct
• m=QC

Multiple Choice

q = +6,000 J

• Endothermic

• Exothermic

Multiple Choice

q = -300 J

• Endothermic

• Exothermic

Multiple Choice

How much heat is needed to raise the temperature of 50 g of iron by 15°C? (specific heat of iron = 0.444 J/g°C)

• 333 J

• -333 J

• 33300 J

• -3330 J

System vs. Surroundings

• Energy must always be conserved; the energy of the universe is constant

• Endothermic reactions = heat into the system, out of the surroundings

• Exothermic reaction = heat out of the system, into the surroundings

Multiple Choice

A sunflower makes food during photosynthesis.

• exothermic

• endothermic

Multiple Choice

Ice cubes in your glass of soda melt.

• endothermic

• exothermic

Multiple Choice

Your family uses candles to see when the electricity goes out.

• exothermic

• endothermic

Multiple Choice

Baking pizza in the oven

• endothermic

• exothermic

Multiple Choice

The initial temperature was measured to be 20^oC and the final temperature was 10^oC. The reaction was

• exothermic

• endothermic

Multiple Choice

The initial temperature was measured to be 20^oC and the final temperature was 45^oC. The reaction was

• exothermic

• endothermic

Enthalpy

• is the measure of heat transfer (ΔH) CHANGE IN HEAT ENERGY

• Positive ΔH is an endothermic reaction, the system added heat

• Negative ΔH is an exothermic reaction, the system lost heat

Multiple Choice

2H₂O + 5500J --> 2H₂ + O₂

• Endothermic

• Exothermic

Multiple Choice

F₂ + 2NaCl --> 2NaF + Cl₂ + 400J

• Endothermic

• Exothermic

Multiple Choice

Heat of reactants = 700J

Heat of products = 900J

What is the q?

• 200 J

• -200 J

Multiple Choice

Heat of reactants = 1500J

Heat of products = 400J

Endothermic or exothermic?

• exothermic

• endothermic

Multiple Choice

Heat of reactants = 70J

Heat of products = 100J

Endothermic or exothermic?

• exothermic

• endothermic

Activation Energy

• Activation Energy is the energy required to start a chemical reaction

• A.E. is always higher than the start point or end point

• The end point (products) give information on endothermic/exothermic

Multiple Choice

What is the Heat of Reaction  $\Delta H$  for this reaction?

• -200 KJ

• 200 KJ

• 400 KJ

• -300 KJ

Multiple Choice

What type of reaction is this?

• Exothermic

• Endothermic

• Energy Producing

• No way to tell

Multiple Choice

Energy is _____ in this reaction

• absorbed

• released

Multiple Choice

This energy curve is best described as an...

• endothermic reaction

• exothermic reaction

Multiple Choice

Energy is __________ in this reaction

• absorbed

• released