M = m/L
moles of CaO = 2.75g / molar mass
2.75g/ 56.08g = 0.049moles CaO
155mL / 1000 = 0.155 L
M= 0.049moles/0.155L
M=0.316
Answer:
Joseph Black discovered carbon dioxide.
Explanation:
Hey there!
1 mole has 6.022 x 10²³ atoms.
Multiply that by 3.2 because we have 3.2 moles.
3.2 x 6.022 x 10²³
1.9 x 10²⁴
There are 1.9 x 10²⁴ atoms in 3.2 moles of chromium.
Hope this helps!
If a 22. 5 mm copper (ii) solution(solution a) had an absorbance of 1. 65. Then, the absorbance if 8 ml of solution a was used to prepare a 20. 0 ml of a new copper (ii) solution is 918.84.
According to Beer-Lambert law, the absorbance (A) of a substance depends on its concentration (c)
A = ε . l. c
where,
ε: absorptivity of the species
l: optical path length
A 22.5 mM phosphate solution (solution A) had an absorbance of 1.012.
A = ε . l . c
1.65 = ε . l . 22.5 mM
ε . l = 37.125 mM⁻¹
We will calculate the concentration of the second solution using the dilution rule.
C₁ . V₁ = C₂ . V₂
22.5mM . 8 mL = C₂ . 20.0 mL
C₂ = 24.75 mM
The absorbance of the second solution is:
A = (ε . l ). c
A = (37.125 mM⁻¹) x 24.75 mM = 918.84
Thus, we find that the value of absorbance is 918.84.
Learn more about absorption:
brainly.com/question/23938376
#SPJ4