Answer:
Aluminium.
Explanation:
The above electronic configuration can be written in a simplified form as shown below:
1s² 2s²2p⁶ 3s²3p¹
Next, we shall determine the number of electrons in the atom of the element as follow:
Number electron = 2 + 2 + 6 + 2 + 1
Number of electron = 13
Next, we shall determine the number of protons.
Since the element is in its neutral state,
The number of electrons and protons are equal i.e
Proton = Electron
Number of electron = 13
Proton = Electron = 13
Proton = 13
Next, we shall determine the atomic number of the element.
The atomic number of an element is simply the number of protons in the atom of the element i.e
Atomic number = proton number
Proton = 13
Atomic number = 13
Comparing the atomic number of the element with those in the periodic table, the element with the above electronic configuration is aluminium since no two elements have the same atomic number.
I think the answers are A, C, A.
Answer:
1.05 mol
Explanation:
Step 1: Given data
- Molarity of sulfuric acid (M): 1.325 M (1.325 mol/L)
- Volume of solution (V): 395 mL (0.395 L)
Step 2: Calculate the moles of sulfuric acid (n)
We will use the following expression.
M = n/V
n = M × V
n = 1.325 mol/L × 0.395 L = 0.523 mol
Step 3: Calculate the moles of H⁺
H₂SO₄ dissociates completely according to the following equation.
H₂SO₄ ⇒ 2 H⁺ + SO₄²⁻
The molar ratio of H₂SO₄ to H⁺ is 1:2. The moles of H⁺ are 2/1 × 0.523 mol = 1.05 mol.
Answer:
When mechanical waves strike a barrier, at least part of the energy of the waves will be reflected back into the media from which they came.
Explanation:
In PV = nRT, n is the number of moles. When 8 grams of oxygen are present,
n = 8/32 = 1/4
So PV = RT/4
