Elements. Elements cannot be further separated as they are the most basic substances.
Answer:
Number of molecules = 23.9 × 10²³ molecules
Number of moles = 3.97 mol
Explanation:
Mass of HNO₃ = 250 g
Number of moles = ?
Number of molecules = ?
Solution:
Number of moles = mass / molar mass
Number of moles = 250 g/63 g/mol
Number of moles = 3.97 mol
Number of molecules:
The given problem will solve by using Avogadro number.
It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.
The number 6.022 × 10²³ is called Avogadro number.
For example,
18 g of water = 1 mole = 6.022 × 10²³ molecules of water
1.008 g of hydrogen = 1 mole = 6.022 × 10²³ atoms of hydrogen
For 250 g of HNO₃:
250 g/ 63 g/mol = 3.97 mole
3.97 × 6.022 × 10²³ molecules = 23.9 × 10²³ molecules
89.1% Au
The molar mass of Au2O3 is 2(196.97) + 3(16.00) = 441.94 g/mol
The mass percent of Au is therefore 2(196.97) / 441.94, which is 393.94/441.94 = 0.891 —> 89.1%
Answer:
7.08
Explanation:
To solve this problem we'll use the <em>Henderson-Hasselbach equation</em>:
- pH = pka + log
![\frac{[A^-]}{[HA]}](https://tex.z-dn.net/?f=%5Cfrac%7B%5BA%5E-%5D%7D%7B%5BHA%5D%7D)
Where is the ratio of [sodium formate]/[formic acid] and pka is equal to -log(Ka), meaning that:
- pka = -log (1.8x10⁻⁴) = 3.74
We<u> input the data</u>:
- 4.59 = 3.74 + log
And<u> solve for </u>:
- 0.85 = log
=
- = 7.08
Answer:
The amount of mass in a certain volume
Explanation:
