Answer:
Earth's average surface gravity is about 9.8 meters per second per second. When an object is tossed off a building top or a cliff apex, for instance, it accelerates toward the ground at 9.8 meters per second per second. The Moon's surface gravity is about 1/6th as powerful or about 1.6 meters per second per second,
Explanation:
Electrons in an atom can be classified as core electrons and valence electrons. Valence electrons are those electrons which are present in valence shell and participates in bond formation. While, Core electrons are all remaining electrons which are not present in valence shell, hence not take part in bonding.
Atomic number of Selenium (Se) is 34 hence it has 34 electrons with following electronic configuration;
1s², 2s², 2p⁶, 3s², 3p⁶, 4s², 3d¹⁰, 4p⁴
From electronic configuration it is found that the valence shell is 4, and the number of electrons present in valence shell are 6. So,
Core Electrons = Total Electrons - Valence Electrons
Core Electrons = 34 - 6
Core Electrons = 28
Result:
There are 28 core electrons in Selenium.
If I understand this right, the two elements are Nickel and Copper, elements 28 and 28, respectively. A nickel is worth 5 cents, and a penny, originally comprised of copper, is worth one - the total being six cents.
When an acid is neutralized by a base, that means moles of H+ = moles of OH-
moles of H+ = 0.5 M * 0.025 L HCl = 0.0125 moles H+
moles of OH- should be equal to 0.0125 moles, so
0.0125 moles = (x) * 0.025 L NaOH
x is the concentration of NaOH, which we want to find.
x = 0.5 M
The correct answer is C) 0.5 M.
