Ions are formed when atoms lose or gain electrons in order to fulfill the octet rule and have full outer valence electron shells. When they lose electrons, they become positively charged and are named cations. When they gain electrons, they are negatively charged and are named anions.
7. D. 668 joules
8. B. 3 grams
<h3>Further explanation</h3>
Given
2 grams of water
6768 joules of energy
Required
Energy
Mass of water
Solution
The heat to change the phase can be formulated :
Q = m.Lf (melting/freezing)
Q = m.Lv (vaporization/condensation)
Lf=latent heat of fusion
Lv=latent heat of vaporization
7. phase change (ice to water)⇒Heat of fusion water=334 J/g
Q = 2 g x 334 J/g
Q = 668 J
8. phase change(water to vapor)⇒heat of vaporization water=2260 J/g
6768 J = m x 2260 J/g
m = 3 g
Using the ideal gas law: PV = nRT; and given the initial conditions:
V1 = 20 cc
T1 = 25 C or 298 K
We are asked to determine the volume at 0 C or 273 K. Assume that the pressure and number of moles are constant. Thus,
V/T = constant, then
V1/T1 = V2/T2
Solve for V2:
20 cc/ 298 K = V2/ 273 K
V2 = 18.32 cc
Answer:
The atoms in the cup of coffee have more energy.
Explanation:
The difference between the hot cup of coffee and the piece of ice is their temperature. The hot cup of coffee has a higher temperature than the ice.
The relationship between the energy and temperature is a direct relationship. This means that higher temperature means higher kinetic energy and vice versa.
Since the hot cup of coffee has a higher temperature, it means it also have the highest amount of energy. The correct option is;
The atoms in the cup of coffee have more energy.