<em>In the late 1800's, experiments using cathode ray tubes led to the discovery of the;</em>
Electron(s)
<u>It was founded that many different metals release cathode rays, and that cathode rays were made of electrons, very small negatively charged particles.</u>
Explanation:
If the number of atoms of each element in reactants is not equal to the number of atoms of each element present in product, then the chemical equation is called unbalanced chemical equation
The weight of the balloon is irrelevant because it is the gas that lifts it in the air. We are already given with the required volume, so we use this instead. The atomic weight of zinc is 65.38 g/mol. Assuming ideal gas behavior,
PV=nRT
P(475 mL)(1 L/1000 mL) = (1.85/65.38)(0.0821 L·atm/mol·K)(21.5 + 273)
P = 1.44 atm
Then, we use this pressure and the volume to find the moles of zinc.
(1.44 atm)(475 mL+1 mL)(1 L/1000 mL) = n(0.0821 L·atm/mol·K)(21.5 + 273)
Solving for n,
<em>n = 0.02836 moles of zinc</em>
Actual question from source:-
A 3.96x10-4 M solution of compound A exhibited an absorbance of 0.624 at 238 nm in a 1.000 cm cuvette. A blank had an absorbance of 0.029. The absorbance of an unknown solution of compound A was 0.375. Find the concentration of A in the unknown.
Answer:
Molar absorptivity of compound A = 
Explanation:
According to the Lambert's Beer law:-
Where, A is the absorbance
l is the path length
is the molar absorptivity
c is the concentration.
Given that:-
c = 
Path length = 1.000 cm
Absorbance observed = 0.624
Absorbance blank = 0.029
A = 0.624 - 0.029 = 0.595
So, applying the values in the Lambert Beer's law as shown below:-

<u>Molar absorptivity of compound A =
</u>