Assignment #2 from Chemistry CD ROM

Assignment #2 from Chemistry CD ROM
Specific Heat

The following problems are based on Chapter 1: Problems 15 to 19 from the CD ROM. Check out how those ones are solved and also read section 1.10 of the Study Guide and the worked example for specific heat. E-mail me and/or the class e-mail list if you are having trouble figuring out how to do any of this.

The CD ROM uses different notation and units than those from class. Instead of giving specific heat in units of J/kgK it uses J/gc° (The conversion equation is 1000 J/kgK = 1 J/gc° since Kelvin and celsius degrees are the same and the only real difference is the kilograms vs. grams.) The CD also uses SH for specific heat rather than c so the equation is written:
q = m (SH) DT instead of q = m c DT .

1. If 4.5 kg of water is heated from 20.2 to 28.2 °C, how much heat (energy) does the water absorb?

2. One kilogram of water is heated with an immersion heater. The temperature of the water goes from 10.0 to 35.0 °C. How many joules are absorbed?

3. A sample of metal absorbs 11.7 J when it is warmed from 20.0 to 25.6 °C. What piece of information is needed in order for you do determine the value of the specific heat of this substance?

4. If 6.0 kg of a substance loses 83,700 J while its temperature goes from 28.2 to 23.2 °C, what is the specific heat of the substance? Specific heat values are ALWAYS positive.

5. 50,200 J are lost by a sample of water with a mass of 3.5 kg. The initial temperature of the water was 16.0 °C. What is the final temperature of the water?

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