2 moles x 6.02 x 10^23 maybe
When Be(OH)₂ dissolves it dissociates into the following ions
Be(OH)₂ --> Be²⁺ + 2OH⁻
molar solubility is the number of moles that dissolve in 1 L of solution
If the molar solubility of Be(OH)₂ is 'x', molar solubility of Be²⁺ and OH⁻ ions are x and 2x respectively.
ksp is solubility constant for Be(OH)₂
ksp = [Be²⁺][OH⁻]²
6.92 * 10⁻²² = [x][2x]²
4x³ = 6.92 * 10⁻²²
x³ = 1.73 * 10⁻²²
x = 5.57 * 10⁻⁸ mol/L
molar solubility of Be(OH)₂ is 5.57 * 10⁻⁸ mol/L
Answer:
0 %
Explanation:
As we know 10.81 is the average atomic mass of boron which can not be contained by a single boron atom. Therefore, when isolated, a single boron atom will weight either 10 amu for ¹⁰B and 11 amu for ¹¹B respectively.
The average atomic mass is calculated as;
Atomic Mass of ¹⁰B = 10
Atomic Mass of ¹¹B = 11
Natural Abundance of ¹⁰B = 20 %
Natural Abundance of ¹¹B = 80 %
So,
Average Atomic Mass = (10 × 0.2) + (11 × 0.8)
Average Atomic Mass = 2 + 8.8
Average Atomic Mass = 10.8
Answer:
A. A physical change took place during this experiment
Explanation:
A physical change is one of the changes that occurs in a reaction. It is a kind of change characterized by no change to the chemical composition of the substances involved. It involves reactions such as melting, change of state, freezing, boiling etc.
According to this question, Lydia added 50 grams of sugar to 200 milliliters of water, then, stirred the mixture, until the sugar eventually dissolved into the water and couldn’t be seen. This change involved no change in color, odor, or temperature. Hence, Lydia's experiment represents a PHYSICAL CHANGE because only DISSOLUTION occured.
In an experiment, Lydia added 50 grams of sugar to 200 milliliters of water. She stirred the mixture, and the sugar eventually dissolved into the water and couldn’t be seen. The volume of the solution increased, but there was no noticeable change in color, odor, or temperature. Which statement best describes what happened in Lydia’s experiment? A. A physical change took place during this experiment. B. A chemical change took place during this experiment. C. A compound was formed during this experiment. D. A heterogeneous mixture was