15.0 g of water is heated from 5 °C up to 37 °C. How much energy is absorbed by the water? (The specific heat of liquid water is 4.184 J/g °C.)

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1) 15.0 g of water is heated from 5 °C up to 37 °C. How much energy is absorbed by the water? (The specific heat of liquid water is 4.184 J/g°C.)

2)How many joules of energy is required to bring a five-pound (1 pound = 454 g) bag of ice from its freezer temperature at -20.0°C up to 0°C? The specific heat of ice is 2.10 J/g×°C.

3) A 50.0 mg tissue sample is taken from a patient for diagnosis. While waiting for testing, the sample is stored in a -80.0°C freezer. How much energy is released when the sample is cooled from 20.0°C down to the freezer temperature? You may assume the specific heat of the tissue sample is 3.47 J/g×K.

1. 1 mole of anything contains 6.022x10^23 pieces  

d  

2. a  

3. c, number  

5. 1.24x10^24atoms / 6.022x10^23atoms/mole = 2moles h2 atoms  

6. fe2br3 mass = 2moles x mass fe + 3 moles x mass br  

molar mass = grams / number of moles = g/mole  

to find moles = g / molar mass  

to find mass = g = molar mass / moles

the molecules move in straight line until they collide with each other or with the walls of the container. collisions are perfectly elastic; when two molecules collide, they change their directions and kinetic energies, but the total kinetic energy is conserved.

explanation: