Answer:
353 grams per mole
Explanation:
Candle wax is defined by the chemical formula C25H52 and has a molar mass of 353 grams per mole.
Answer:
Hint As we know that the concept of mole is mainly to calculate the entities at the microscopic level that is ions, particles, molecules, electrons or atoms etc. It is found that mole is having the symbol mol.
Complete Step by step solution:
- As we are being provided with the information that there is 15 grams of lithium. As we know that the molar mass of lithium is 6.94 g/mol.
- As we know that mole is the amount of substance that has entities as there are atoms exactly in 12 g of carbon isotope. We should note that the number of entities in one mole is important because it is called the Avogadro constant. The numeric value of this constant is 6.022×1023.
- Firstly we will write the given mass as:
156.022×1023
- Now, we can find the number of moles by the formula of moles that is given mass of the substance divided by the molar mass of the substance.
moles=given massmolar mass⟹156.022×10236.94⟹15×6.946.022×1023⟹17.28×10−23moles
- Hence, we can conclude that there are 17.28×1023 moles in 15 grams of lithium.
Note:
- If we want to calculate the number of moles of an individual entity, like say A, that is dissolved in a solution of an entity say B (A+B), then we can do so by using the concept of mole fraction. The formula of mole fraction is given as moles of a substance divided by the total number of moles.
- We should not forget to write the unit after solving the solution. Explanation:
Na is the reducing agent since it is being oxidized
Answer:
The average atomic mass of given element is 20.18 amu.
Explanation:
Given data:
Abundance of 1st isotope mass 20 amu = 90.92%
Abundance of 2nd isotope mass 21 amu = 0.257%
Abundance of 3rd isotope mass 22 amu = 8.82%
Average atomic mass = ?
Solution:
Average atomic mass = (abundance of 1st isotope × its atomic mass) +(abundance of 2nd isotope × its atomic mass) + (abundance of 3rd isotope × its atomic mass) / 100
Average atomic mass = (90.92×20)+(0.257×21)+(8.82×22) /100
Average atomic mass = 1818.4 + 5.397 +194.04 / 100
Average atomic mass = 2017.819 / 100
Average atomic mass = 20.18 amu.
The average atomic mass of given element is 20.18 amu.
Explanation:
For all of the questions, do the following calculation
As an example, I'll do question 1
