How many joules are released when 30.0 g of H2O(g) condenses at 100°C and cools to 10°C

Heat released : 79086 J

Condenses :

1. phase change (gas - liquid) : heat of vaporization (ΔH vap for water = 2260 J/g)

2. cools from 100 - 10 : (Q=m.cΔT)

1. Q=m.ΔH vap

2. Q=mc.ΔT(c water = 4.18 J/g C)

Q tot = 67800 + 11286 = 79086 J

what's the

in scientific notation, the value of the  speed of light in a vacuum

  will be written as 2.995 * 10^8. when this value is represented in the form of

  a * 10^b, then, a = 2.995 and b = 8.

the value of the speed of light in a vacuum given above can also be rounded up to approximately 300000000. in this case, the scientific notation will be written as 3 *10^8.