a) (NH4)2SO4 --- 1 mole of it contains 2 moles of N, 8 moles of H, 1 mole of S, and 4 moles of O.
MM = (2 moles N x 14.0 g/mole) + (8 moles H x 1.01 g/mole) + (1 mole S x 32.1 g/mole) + (4 moles O x 16.0 g/mole) = 132 g/mole.
6.60 g (NH4)2SO4 x (1 mole (NH4)2SO4 / 132 g (NH4)2SO4) = 0.0500 moles (NH4)2SO4
b) The molar mass for Ca(OH)2 = 74.0 g/mole, calculated like (NH4)2SO4 above.
4.5 kg Ca(OH)2 x (1000 g / 1 kg) x (1 mole Ca(OH)2 / 74.0 g Ca(OH)2) = 60.8 moles Ca(OH)2
Answer:
Potassium
General Formulas and Concepts:
<u>Chem</u>
- Reading a Periodic Table
- Periodic Trends
- Ionization Energy - energy required to remove an electron from a given element
- Coulomb's Law
- Shielding Effect
- Z-effective and Forces of Attraction
Explanation:
The Periodic Trend for 1st Ionization Energy is increasing up and to the right. That means He would have the highest I.E and therefore take the most amount of energy to remove an electron.
Potassium and Gallium are both in Period 4. Potassium is element 19 and Gallium is element 31.
Potassium's electron configuration is [Ne] 4s¹ and Gallium's electron configurations is [Ne] 4s²3d¹⁰4p¹. Since both are in Period 4, they have the same number of core e⁻. Therefore, the shielding effect is the same.
However, since Gallium is element 31, it has 31 protons compared to Potassium, which is element 19 and has 19 protons. Gallium would have a greater Zeff than Potassium as it has more protons. Therefore, the FOA between the electrons and nucleus of Ga is much stronger than that of K. Thus, Ga requires <em>more</em> energy to overcome those FOA to remove the 4p¹ e⁻. Since K has less protons, it will have a smaller Zeff and thus less FOA between the e⁻ and nucleus, requiring <em>less</em> energy to remove the 4s¹ e⁻.
Answer: 3d
Explantion:
1) Period 4 contains the elements with atomic numbers 19 through 36.
2) The elements with atomic numbers 19 (K) and 20 (Ca) fill the orbital 4s.
3) After that, as Aufbau's rule may help you to remember, the energy of the orbitals 3d is lower than the energy of the orbtitals 4p. So, the element 21 (Sc) start fillind the orbital 3d.
There are ten 3d orbitals, so the elements 21 through 30 fill the 3d orbitals.
Those elements, called transition metals are: Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn.
When the 3d orbitals are full, the next elements in the same period 4, fill the six 4p orbitals.
Answer:
If the ambient temperature around a piece of ice increases, the temperature of the ice will increase as well. However, this steady increase in temperature stops as soon as the ice reaches its melting point. At this point, the ice undergoes a change of state and turns into liquid water, and its temperature won't change until all of it has melted. You can test this with a simple experiment. Leave a cup of ice cubes in a hot car and monitor the temperature with a thermometer. You'll find that the icy water remains at a frosty 32 degrees Fahrenheit (0 degrees Celsius) until all of it has melted. When that happens, you'll notice a quick temperature rise as the water continues to absorb heat from the inside of the car.
