Answer:
Option D - 10,000 years ago in the Middle East
Answer:
0.550
Explanation:
The absorbance (A) of a substance depends on its concentration (c) according to Beer-Lambert law.
A = ε . <em>l</em> . c
where,
ε: absorptivity of the species
<em>l</em>: optical path length
A 45 mM phosphate solution (solution A) had an absorbance of 1.012.
A = ε . <em>l</em> . c
1.012 = ε . <em>l</em> . 45 mM
ε . <em>l</em> = 0.022 mM⁻¹
We can find the concentration of the second solution using the dilution rule.
C₁ . V₁ = C₂ . V₂
45mM . 11mL = C₂ . 20.0 mL
C₂ = 25 mM
The absorbance of the second solution is:
A = (ε . <em>l</em> ). c
A = (0.022 mM⁻¹) . 25 mM = 0.55 (rounding off to 3 significant figures = 0.550)
The answer is (3) 0.200 kJ
Hope I helped!
Answer:
Reaction mechanism has been given below
Explanation:
- Propanoyl chloride contains an electrophilic carbonyl center to give nucleophilic acyl substitution reaction by removing Cl group with a strong nucleophile like methylmagnesium bromide.
- Two equivalent of methyl magnesium bromide react with cabonyl center followed by protonation of negatively charged oxygen atom gives 2-methyl-2-butanol.
- In the first step, nucleophilic acyl substituion occurs. In the second step, nucleophilic addition occurs. In the third step, protonation occurs.
- Reaction mechanism has been shown below.
The combination of an atom with other atom is bonding. Or break apart from other substance is breaking of interaction.
The bonding or interaction (inter-atomic) are due orbitals and electrons present in these orbitals
The atom consists of
a) a central nucleus which has proton and neutrons: they do not take part in chemical reactions
b) the part other than nucleus which has shells, sub shells and orbitals
These orbitals have electrons.
So the outer part of nucleus takes part in any combination with other substance
