The molarity of a 250. mL H2SO4 solution that was made from a 20.0 mL of a 10.0 M stock solution is 0.8M.
<h3>How to calculate molarity?</h3>
The molarity of a solution can be calculated using the following expression:
CaVa = CbVb
Where;
- Ca = concentration of acid
- Cb = concentration of base
- Va = volume of acid
- Vb = volume of base
In this question;
- Ca = ?
- Va = 250mL
- Cb = 10M
- Vb = 20mL
Ca × 250 = 10 × 20
250Ca = 200
Ca = 200/250
Ca = 0.8M
Therefore, the molarity of a 250. mL H2SO4 solution that was made from a 20.0 mL of a 10.0 M stock solution is 0.8M.
Learn more about molarity at: brainly.com/question/2817451
The wavelength of the photon required to excite this molecule from its ground state, to its first excited state is 1240 nm.
This is given by the equation:
wavelength = hc/(E_homo - E_lumo)
where h is Planck's constant =6.626070 * 10^-34 J.m , c is the speed of light = 3.0 x 10^8 m/s^2, and E_homo and E_lumo are the energies of the highest occupied molecular orbital and the lowest unoccupied molecular orbital, respectively.
In this particular case, the wavelength of the required photon would be:
wavelength = hc/(-2.42 hartree - 0.65 hartree)
= 6.626070 * 10^-34 X 3.0 x 10^8 / (-3.07)
= 1240 nm
Hence , The wavelength of the photon required to excite this molecule from its ground state, to its first excited state is 1240 nm.
Learn more about wavelength at : brainly.com/question/13533093
#SPJ4
Answer:
900g
Explanation:
Given parameters:
Number of moles of Sc = 20moles
Unknown:
Mass of Sc = ?
Solution:
To find the mass of the scandium given, we use the expression below:
Mass = Number of moles x molar mass
Molar mass of Sc = 45g/mol
So;
Mass of Sc = 20 x 45 = 900g
The answer would be 20% (B)
Answer: A, Nucleus
B, Cell memebrane
C, vacuole
D, Chloroplast, mitocondria, amyloplast.
Explanation:
These only work if this is a plant cell which you did not specify.
