Answer: A) 0.20 L
Explanation:
Molarity of a solution is defined as the number of moles of solute dissolved per Liter of the solution.
According to the neutralization law,
![M_1V_1=M_2V_2](https://tex.z-dn.net/?f=M_1V_1%3DM_2V_2)
where,
= molarity of stock
solution = 10.0 M
= volume of stock
solution = ?
= molarity of dilute
solution = 0.50 M
= volume of dilute
solution = 4.0 L
![10.0\times V_1=0.50\times 4.0](https://tex.z-dn.net/?f=10.0%5Ctimes%20V_1%3D0.50%5Ctimes%204.0)
![V_1=0.20L](https://tex.z-dn.net/?f=V_1%3D0.20L)
Therefore, the volume of 10.0 M
solution needed to prepare 4.0 L of 0.50 M
is 0.20 L
Answer:
![\text{ }1.25\times10^{23}\text{ formula units}](https://tex.z-dn.net/?f=%5Ctext%7B%20%7D1.25%5Ctimes10%5E%7B23%7D%5Ctext%7B%20formula%20units%7D)
Explanation:
Here, we want to calculate the number of formula units in the given molecule
We start by getting the number of moles
To get the number of moles, we have to divide the mass given by the molar mass
The molar mass is the mass per mole
The molar mass of calcium bromide is 200 g/mol
Thus, we have the number of moles as follows:
![\frac{41.5}{200}\text{ = 0.2075 mol}](https://tex.z-dn.net/?f=%5Cfrac%7B41.5%7D%7B200%7D%5Ctext%7B%20%3D%200.2075%20mol%7D)
The number of formula units in a mole is:
![1\text{ mole = 6.02 }\times10^{22}\text{ formula units}](https://tex.z-dn.net/?f=1%5Ctext%7B%20mole%20%3D%206.02%20%7D%5Ctimes10%5E%7B22%7D%5Ctext%7B%20formula%20units%7D)
The number of formula units in 0.2075 mole will be:
Wouldn't it be 100? 150 - 50 would equal 100. Unless I'm not seeing something.
Answer:
Explanation:
Sodium and potassium are present in group 1A. Both are alkali metals.
The atomic number of sodium is 11 and potassium is 19. Sodium is present in period 3rd while potassium is present in period 4th.
Electronic configuration of sodium:
Na₁₁ = 1s² 2s² 2p⁶ 3s¹
K₁₉ = 1s² 2s² 2p⁶ 3s² 3p⁶ 4s¹
It can be seen in electronic configuration that in case of sodium the valance electron is present in third energy level while in case of K outer most electron is present in 4th energy level. So atomic structure of sodium has three energy level and K has four energy level that's why radius of potassium is greater than sodium because its the distance from center to outer most electronic shell.
Moreover as we move down the group atomic radii increased with increase of atomic number. The addition of electron in next level cause the atomic radii to increased. The hold of nucleus on valance shell become weaker because of shielding of electrons thus size of atom increased.
Answer:
1. 3.02 liters
2. 302.2 liters
3. 2.83 grams
Explanation:
Question 1.
Let's convert the molarity in mass.
Molarity is mol/L, so if we convert the moles to mass, we are talking about a mass, in 1L of solution. (mol . molar mass)
0.5 mol . 110.98 g/m = 55.49 g
Now we can make a rule of three:
If 55.49 grams of chloride are in 1L of solution
then 167.5 g of chloride are in (167.5g . 1L) / 55.49 g = 3.02L
For question 2 and 3, we assume STP, where pressure is 1 atm and T° is 273K. - Standard conditions of temperature and pressure (STP)
Let's apply the Ideal gases law equation
P . V = n . R .T
1 atm . V = 13.5 moles . 0.082 l.atm / mol .K . 273K
V = (13.5 moles . 0.082 l.atm / mol .K . 273K) / 1 atm = 302.2 liters (question 2)
Question 3.
1 atm . 31.7 L = n . 0.082 l.atm / mol.K . 273K
(1 atm . 31.7 L ) / (0.082 l.atm / mol.K . 273K) = 1.41 moles → n
Let's convert moles to mass ( mol . molar mass)
1.41 mol . 2g/mol = 2.83 grams