Answer:Answer: The step that is NOT necessary to complete before a cuvette is placed into the spectrophotometer is option B (Write, in ink, either sample or blank on the side of the cuvette to keep track of them)
Explanation: spectrophotometer is an instrument used to measure the light intensity absorbed after being passed through a solution. Before the absorbance of the sample solution, a solvent solution called blank is used for the calibration of the machine and this blank solvent is placed in a cuvette. The procedure usually comes first before the main sample is processed. Therefore there is no need to
Write, in ink, either sample or blank on the side of the cuvette to keep track of them. This is so since sample and blank is not absorbed at the same time by the machine.
Answer:
mole
Explanation:
The mole in chemistry is used to represent the amount of any substance. Just like quantifying everyday things like a dozen, score, gross etc, it is a convenient unit of quantity of particles. A mole denotes 6.02 x 10²³particles of a susbstance.
Therefore, a mole is the standard unit(SI) for the amount of isopropyl alcohol in a beaker.
<h2>Answer </h2>
Matter
<u>Explanation </u>
A matter has distinct properties and composition that never vary. The matter is anything which possesses mass and occupies space. The matter has different characteristics and a distribution that does not change from unit to unit. Materials which cannot be disintegrated into simpler materials. Each is made of only one kind of atom in subatomic level. For example, a chair, table, and similar everything that has mass and occupies space is matter.
Answer:
0.121 moles of aluminum metal are required to produce 4.04 L of hydrogen gas at 1.11 atm and 27 °C by reaction with HCl
Explanation:
This is the reaction:
2 Al(s) + 6 HCl(aq) → 2 AlCl₃ (aq) + 3 H₂(g)
To make 3 moles of H₂, we need 2 moles of Al.
By conditions given, we will find out how many moles of H₂ do we have.
Let's use the Ideal Gas Law
P. V = n . R . T
1.11 atm . 4.04L = n . 0.082 L.atm/mol.K . 300K
(1.11 atm . 4.04L) / (0.082 mol.K/L.atm . 300K) = n
0.182 mol = n
So the rule of three will be:
If 3 moles of H₂ came from 2 moles of Al
0.182 moles of H₂ will come from x
(0.182 .2) / 3 = 0.121 moles
