The document provides information about heat transfer and chemical reactions: 1) It asks which of four substances (iron, diamonds, vegetable oil, or copper) would heat up the fastest by 5°C and how much heat would be required. 2) It also asks which would be best at storing heat or losing it slowest. 3) It reviews homework problems involving calculating heat (Q) transferred using specific heat (c), mass (m), and change in temperature (ΔT). 4) It defines endothermic and exothermic reactions based on whether heat is absorbed (Q is positive) or released (Q is negative) and provides examples.

1. Do Now: Tuesday 5/1
Which of the following substances would be the
o
quickest to heat up by 5 C? How much heat would it
take?
• 10 grams of iron
• 10 grams of diamonds
• 10 grams of vegetable oil
• 10 grams of copper
Which of these 4 would be the best at storing heat
(i.e. – it would lose heat the slowest)?

2. Yesterdays Assignment:
1. a) Q = mc∆T = 550(4.184)(18.0 – 12.0) = 13807.2 J
b) Heat is absorbed (Q is “+”)
2. Q = mc∆T = 640(0.381)(26 – 375) = -85100.16 J
3. a) Q = mc∆T = 1500(0.473)(13 – 880) = -615136.5 J
b) Heat is released (Q is “-”)
4. a) Heat is absorbed because Q is “+”.
b) Temperature will increase.

3. Yesterdays Assignment:
5. Properties if endothermic reactions:
- Absorb energy (“endo” = in)
- Q>0
- Feel cold
6. Properties of exothermic reactions:
- Release energy (“exo” = out)
- Q<0
- Feel hot

4. Yesterdays Assignment:
7. “Energy” (heat) is on the product or output side,
therefore it’s being released and this is exothermic.
8. “Energy” (heat) is on the product or output side,
therefore it’s being released and this is exothermic.
9. “Energy” (heat) is on the reactant or input side,
therefore it’s being absorbed and this is
endothermic.

5. Yesterdays Assignment:
13. Ice melting  it absorbs heat so that it could
melt, thus endothermic.
14. Candle burning  it releases heat thus feeling hot.
This means exothermic.
15. Cooking an egg  heat is absorbed by the egg,
thus cooking its insides. This is
endothermic.

6. Group Quiz:
Use your notes
Work with your group