<span>As we know through the principle of conservation of energy, energy can neither be created nor destroyed. Therefore, the energy removed from the water in order to make it freeze is absorbed by the surroundings. This is why the surroundings in which freezing is taking place are below freezing. This is more easily illustrated in the example of condensation. If you were to hold a plate over a pot of boiling water, some of the water would give its energy to the plate and condense on its surface.</span>
Answer: Mass of gas is 0.001 pounds.
Explanation:
Density is defined as the mass contained per unit volume.
Given : Mass of gas = ?
Density of gas = 
Volume of gas = 389 ml = 0.389 L (1L=1000ml)
Putting in the values we get:
(1g =0.002 lb)
Thus the mass of gas is 0.001 pounds.
Answer is: <span>Mutations sometimes improve the chances of survival for a plant.
</span>Mutations are very important because they change <span>variability in populations and in that way enable evolutionary change.
</span>There are three types of mutations:
1) good or advantageous mutations - <span> improve the chances of survival for a plant.
2) </span>bad or deleterious - decrease the chances of survival for a plant.
3) neutral - not affect he chances of survival for a plant.
Answer:
.
Explanation:
Based on the electron configuration of this ion, count the number of electrons in this ion in total:
.
Each electron has a charge of 
.
Atoms are neutral and have 
charge. However, when an atom gains one extra electron, it becomes an ion with a charge of . Likewise, when that ion gains another electron, the charge on this ion would become 
.
The ion in this question has a charge of . In other words, this ion is formed after its corresponding atom gains two extra electrons. This ion has 
electrons in total. Therefore, the atom would have initially contained 
electrons. The atomic number of this atom would be 
.
Refer to a modern copy of the periodic table. The element with an atomic number of is sulphur with atomic symbol 
. To denote the ion, place the charge written backwards ("
" for a charge of ) as the superscript of the atomic symbol:
.
Answer:
One extraction: 50%
Two extractions: 75%
Three extractions: 87.5%
Four extractions: 93.75%
Explanation:
The following equation relates the fraction q of the compound left in volume V₁ of phase 1 that is extracted n times with volume V₂.
qⁿ = (V₁/(V₁ + KV₂))ⁿ
We also know that V₂ = 1/2(V₁) and K = 2, so these expressions can be substituted into the above equation:
qⁿ = (V₁/(V₁ + 2(1/2V₁))ⁿ = (V₁/(V₁ + V₁))ⁿ = (V₁/(2V₁))ⁿ = (1/2)ⁿ
When n = 1, q = 1/2, so the fraction removed from phase 1 is also 1/2, or 50%.
When n = 2, q = (1/2)² = 1/4, so the fraction removed from phase 1 is (1 - 1/4) = 3/4 or 75%.
When n = 3, q = (1/2)³ = 1/8, so the fraction removed from phase 1 is (1 - 1/8) = 7/8 or 87.5%.
When n = 4, q = (1/2)⁴ = 1/16, so the fraction removed from phase 1 is (1 - 1/16) = 15/16 or 93.75%.
