specific heat

latent heat

Calorimetry

-Q = Q

c

h

Internal Energy

**Internal Energy**

If a 1.5 kg of piece of iron (450) goes from 200 - 75 C, by dropping it in a cup of water (4186), whose temperature goes form 25-75. What is the volume of water? (assume no energy loss)

We'll deal with the change internal energy in Ch 15

**Specific Heat**

How much energy is required to bring .25 kg of water(4186) from 20 - 75 C?

How much heat is lost cooling 1.5 kg of iron (450) from 160 - 75 C?

57600 J

57400 J

.403 L

Phase change

How much energy is needed to bring 2.0kg of lead (130) from 25 C to a liquid state at 327 C (latent heat of fusion is 25000)

128.5 KJ

How much heat is lost bringing 1.5 kg of steam (2010) from 125 C down into water (4186) at 50 C? (latent heat of vaporization is 2,260,000 J/kg)

3780 KJ

What mass of 100 C steam must be added to 1.00 kg of ice at 0 C to yield liquid water at 30 C? (333,000 and 2,260,000)

.180 kg

Calorimetry

When a 290 g piece of iron(450) at 180 c is placed in a 95 g aluminum (900) calorimeter cup containing 250 g of glycerin at 10 C. The final temperature is observed to be 38 C. Estimate the specific heat of glycerin.

2305 J/kgC

A 28 g ice(2100) cube at its melting point is dropped into an insulated cup container of liquid nitrogen. How much nitrogen evaporates if it is at its boiling pt of 77 K and has a latent heat of vaporization of 200,000 J/kg? (assume c is constant for ice and all heat goes to evaporating nitrogen)

58 g

**Determine the latent heat of fusion of mercury using the following calorimeter data: 1.00 kg of solid HG(140) at its melting point of -39.0 C is placed in a 0.620 kg aluminum(900) calorimeter with 0.400 kg of water(4186) at 12.80 C; the resulting equilibrium temperature is 5.06 C.**

**11.1 kJ/kg**

**What is the final temperature if a 250 g block of lead(130) initially at 200 C is dropped into a 150 g aluminum(900) cup containing 750 g of water(4186) initially at 10 C?**

**11.87 C**

**Heat flow rates**

Plug and chug, I'll give all but 1 term and you find it.

"Can we go over convection conduction and radiation. "

"Can we discuss what latent heats means please?"

"I'm struggling with the best way to set up problems involving latent heat. "

"Can you do the last problem on quiz"

"Knowing the specific heat of water is 4186 J/kg C how much heat would be needed to raise 20 kg of water from 10 degrees to 90 degrees? (answer should look like 5800 kJ)"

"In example 14-5, why can you set all the values equal to zero when you're calculating an unknown specific heat?