7. How much energy in KJ is released when 15.0 g of steam at 100.0 degrees Celsius is condensed and then frozen to ice at 0.0 degrees Celsius?

-6.27 kj

Explanation:

Given data:

Energy released = ?

Mass of steam = 15 g

Initial temperature = 100°C

Final temperature = 0°C

Solution:

Specific heat capacity:

It is the amount of heat required to raise the temperature of one gram of substance by one degree.

Specific heat capacity of water is 4.18 j/g.°C

Formula:

Q = m.c. ΔT

Q = amount of heat absorbed or released

m = mass of given substance

c = specific heat capacity of substance

ΔT = change in temperature

ΔT =  0°C - 100°C = -100°C

Q = 15g × 4.18 j/g.°C  × -100°C

Q = -6270 j

J to KJ:

-6270 j/1000 = -6.27 kj

metals are good conductor of electricity. it has free electrons on their surface. according to electron pool theory, each atom present in a metal crystal losses all of its valence electron and as a result a pool of free is form. these pool of electrons are free to move and   conduct electricity easily   while making metal as good conductor.

the correct answer is a. the ability of electrons to flow throughout the metal.

if it's not useful, feel free to report for mistake in answer.