Since Kw= [H⁺][OH⁻], and the concentration of both substances are the same, the equation is now Kw=[H⁺]²
So,
3.31x10⁻¹³ = [H⁺]²
Take the square root= 5.75x10⁻⁷
Then take the negative log to find the pH:
-log(5.75x10⁻⁷) = 6.25
Answer: True!
Explanation: As electrons that are excited move between energy levels, they emit lots and lots of energy, in fact way more energy than ground state electrons (electrons that move within the same energy level) do, thus, making them more unstable.
Answer:
has boiling point of 238 K
Explanation:
Boiling point depends on different intermolecular force such as molecular wight, dipole-dipole attraction force, hydrogen bonding, ionic attraction force.
Homonuclear diatomic molecules are covalent non-polar molecules and thereby free from dipole-dipole attraction force, hydrogen bonding and ionic interaction forces.
Hence, boiling point of homonuclear diatomic molecules depends solely on molecular weight.
We know, higher the molecular weight of a molecule, higher will be its boiling point. This phenomenon can be realized in terms of increasing london dispersion force with increase in molecular weight.
Decreasing order of molecular weight of halogen molecules :
>
>
>
So, decresing order of boiling point of halogen molecules:
>
>
>
Hence
has boiling point of 238 K
Answer:
2.08 moles (3 s.f.)
Explanation:
number of moles
= number of atoms ÷ Avogadro's constant
Avogadro's constant= 6.022 ×10²³
Thus, number of moles
= 1.25×10²⁴ ÷ (6.022 ×10²³)
= 2.08 moles (3 s.f.)
Answer:
74mL
Explanation:
Given parameters:
Molar mass of citric acid = 192g/mol
Molar mass of baking soda = 84g/mol
Concentration of citric acid = 0.8M
Mass of baking powder = 15g
Unknown parameters:
Volume of citric acid = ?
Solution
Equation of the reaction:
C₆H₈O₇ + 3NaHCO₃ → Na₃C₆H₅O₇ + 3H₂O + 3CO₂
Procedure:
- We work from the known parameters to the unknown. From the statement of the problem, we can approach the solution from the parameters of the baking powder.
- From the baking powder, we can establish a molar relationship between the two reactants. We employ the mole concept in this regard.
- We find the number of moles of the baking powder that went into the reaction using the expression below:
Number of moles = 
Number of moles =
= 0.179mole
- From the equation of the reaction, we can find the number of moles of the citric acid:
3 moles of baking powder reacted with 1 mole of citric acid
0.179 moles of baking powder would react with
:
This yields 0.059mole of citric acid
- To find the volume of the citric acid, we use the mole expression below:
Volume of citric acid = 
Volume of citric acid =
= 0.074L
Expressing in mL gives 74mL