Answer:
A solution with a pH of 2
Explanation:
The lower a pH is in a liquid, the more acidic it is. 7 is the neutral pH for a liquid. We usually drink around that pH for water. A pH higher than 7 expresses that the liquid is a base.
Cobalt is often used because it react to magnets while gold does not react to magnets.
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