Answer:
Mass = 114.26 g
Explanation:
Given data:
Number of gold atoms = 3.47×10²³ atoms
Mass in gram = ?
Solution:
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.
1 mole = 6.022 × 10²³ atoms
3.47×10²³ atoms × 1 mol /6.022 × 10²³ atoms
0.58 mol
Mass of gold:
Mass = number of moles × molar mass
Mass = 0.58 mol × 197 g/mol
Mass = 114.26 g
<span>The student is incorrect because helium has 2 valence electrons and it's in group 18 because the first energy level is full. Although helium is placed in Group 18 which generally has 8 valence electrons, it does not have 8 valence electrons as the student suggested. It was grouped together with the noble gases because it exhibits similar properties with them. </span>
Answer:
I think its 1.40M Na^+ we convert to Na3PO4 which means we need 1.40M x (1 mole Na3PO4/3 mol Na^+) = 1.40 x 1/3 = 0.467 M Na3PO4.
Explanation:
There are 3,500 milliseconds in a second.
One second contains 1,000 milliseconds. Three seconds contain 3,000 milliseconds. Half of three hours, therefore, would contain 3,500 milliseconds.
Explanation:
It is given that vapor pressure of pure water at 296 K is 2778.5 Pa.These vapors will result in the formation of an ideal gas.
Now, as water is covered with oil and contains only 1% molecules of water. Hence, the vapor pressure of this mixture will also be equal to the vapor pressure of pure water.
So, vapor pressure of mixture = 1% vapor pressure of pure water
Therefore, 
= 
= 27.785 Pa
Thus, we can conclude that the equilibrium vapor pressure of water above the oil layer is 27.785 Pa.
