Answer:
<em>The correct option is A) The atom has changed over the years.</em>
Explanation:
Option A is not correct because an atom does not change. It remains the same always. The structure of an atom will always contain neutrons, protons and electrons.
Scientific theories tend to change over time as new information is brought up. Novel techniques lead to more advanced experiments and results. As a result, a scientific theory is subjected to change whenever evidence is found for a new theory which challenges the older one.
The atomic theory has changed many times due to novel scientific techniques and experiments.
Answer:
[Ar] 4s²
Explanation:
Ca is the symbol for Calcium. It is the 20th element and it has 20 electrons.
The full electronic configuration for calcium is given as;
1s²2s²2p⁶3s²3p⁶4s²
The condensed electronic configuration is given as;
[Ar] 4s²
Answer:
23.34 %.
Explanation:
- The percentage of water must be calculated as a mass percent.
- We need to find the mass of water, and the total mass in one mole of the compound. For that we need to use the atomic masses of each element and take in consideration the number of atoms of each element in the formula unit.
- <em>Atomic masses of the elements:</em>
Cd: 112.411 g/mol, N: 14.0067 g/mol, O: 15.999 g/mol, and H: 1.008 g/mol.
- <em>Mass of the formula unit:</em>
Cd(NO₃)₂•4H₂O
mass of the formula unit = (At. mass of Cd) + 2(At. mass of N) + 10(At. mass of O) + 8(At. mass of H) = (112.411 g/mol) + 2(14.0067 g/mol) + 10(15.999 g/mol) + 8(1.008 g/mol) = 308.5 g/mol.
- <em> Mass of water in the formula unit:</em>
<em>mass of water</em> = (4 × 2 × 1.008 g/mol) + (4 × 15.999 g/mol) = 72.0 g/mol.
- <em>So, the percent of water in the compound = [mass of water / mass of the formula unit] × 100 = [(72.0 g/mol)/(308.5 g/mol)] × 100 = 23.34 %</em>
Answer:
84672 J
Explanation:
From the question given above, the following data were obtained:
Height (h) = 72 m
Combined mass (m) = 120 Kg
Acceleration due to gravity (g) = 9.8 m/s²
Energy (E) =?
We can obtain the energy by using the following formula:
E = mgh
Where
E => is the energy.
g => is the acceleration due to gravity
m => is the mass.
h => is the height.
E = 120 × 9.8 × 72
E = 84672 J
Thus, the energy is 84672 J
Answer:
removes the fertile B horizon of soil
Explanation:
<em>Wind erosion has the capacity to remove the fertile B horizon of the soil.</em>
The term wind erosion generally refers to the capacity of high-magnitude wind to cause damages to the terrestrial environment. Soils can get their topmost layers removed by a strong wind if there are no barriers such as vegetation to break the speed of the wind.
The topmost layers in most cases consist of humus and the fertile minerals from parent materials. When the topmost layer is lost, the soil becomes unproductive for agriculture.
