Answer:
Dysprosium [Dy]=![[Xe]4f^{10}6s^2](https://tex.z-dn.net/?f=%5BXe%5D4f%5E%7B10%7D6s%5E2)
Americium [Am]=![[Rn]5f^77s^2](https://tex.z-dn.net/?f=%5BRn%5D5f%5E77s%5E2)
Dysprosium is a chemical element with symbol Dy and atomic number of 66. It is a rare earth metal and as it contains partially filled f sub shells, it belongs to f block. Xe is the nearest noble gas and has atomic number of 54.
Americium is a chemical element with symbol Am and atomic number of 95. It is a rare earth metal and as it contains half filled f sub shells, it belongs to f block. Radon is the nearest noble gas and has atomic number of 86.
Answer:
Solution is 4.67% by mass of salt
Explanation:
% by mass is the concentration that defines the mass of solute in 100g of solution.
In this case we have to find out the mass of solution with the data given:
Mass of solution = Mass of solute + Mass of solvent
Solute: Salt → 14.2 g
Solvent: Water → 290 g
Solution's mass = 14.2 g + 290g = 304.2 g
% by mass = (mass of solute / mass of solution) . 100
(14.2 g / 304.2g) . 100 = 4.67 %
78.4 L volume of container is required to hold 3.2 moles of gas.
Explanation:
- STP is defined as the standard temperature and pressure of a gas in room temperature conditions. At STP, one mole of the gas which has Avogadro's number of molecules in it will occupy a volume of 22.4 L.
- So, one mole of a substance or gas will occupy a volume of 22.4 L then the volume of the container needed for 3.2 moles of gas is calculated by multiplying 22.4 L, standard volume with the moles of the gas 3.2 moles.
- Hence, the answer would be 78.4 L.
Answer:
mass of HCl = 243.5426 grams
Explanation:
1- we will get the mass of the reacting gold:
volume of gold = length * width * height
volume of gold = 3.2 * 3.8 * 2.8 = 34.048 cm^3 = 34.048 ml<span>
density = mass / volume
Therefore:
mass = density * volume
mass of gold = </span>19.3 * 34.048 = 657.1264 grams
2- we will get the number of moles of the reacting gold:
number of moles = mass / molar mass
number of moles = 657.1264 / 196.96657
number of moles = 3.3362 moles
3- we will get the number of moles of the HCl:
First, we will balanced the given equation. The balanced equation will be as follows:
Au + 2HCl ......> AuCl2 + H2
This means that one mole of Au reacts with 2 moles of HCl.
Therefore 3.3362 moles will react with 2*3.3362 = 6.6724 moles of HCL
4- we will get the mass of the HCl:
From the periodic table:
molar mass of H = 1 gram
molar mass of Cl = 35.5 grams
Therefore:
molar mass of HCl = 1 + 35.5 = 36.5 grams/mole
number of moles = mass / molar mass
Therefore:
mass = number of moles * molar mass
mass of HCl = 6.6724 * 36.5
mass of HCl = 243.5426 grams
Hope this helps :)
Answer:
The smallest unit of a compound is a molecule, which is made up of atoms held together by bonds.
