Answer:
the unknown substance is a protein
Explanation:
The biuret test is one of the tests for proteins. It can be used to detect peptide linkages. The biuret test is carried out in an alkaline solution. A coordination complex is formed leading to the appearance of a violet color.
Summarily, the biuret method is a colorimetric technique used to test for proteins and peptides. It involves the formation of a purple (violet) complex of Copper salts in alkaline solution.
Hence when the biuret reagent is added to an unknown substance and it turns purple, the unknown substance is a protein
Answer:
A) E° = 4.40 V
B) ΔG° = -8.49 × 10⁵ J
Explanation:
Let's consider the following redox reaction.
2 Li(s) +Cl₂(g) → 2 Li⁺(aq) + 2 Cl⁻(aq)
We can write the corresponding half-reactions.
Cathode (reduction): Cl₂(g) + 2 e⁻ → 2 Cl⁻(aq) E°red = 1.36 V
Anode (oxidation): 2 Li(s) → 2 Li⁺(aq) + 2 e⁻ E°red = -3.04
<em>A) Calculate the cell potential of this reaction under standard reaction conditions.</em>
The standard cell potential (E°) is the difference between the reduction potential of the cathode and the reduction potential of the anode.
E° = E°red, cat - E°red, an = 1.36 V - (-3.04 V) 4.40 V
<em>B) Calculate the free energy ΔG° of the reaction.</em>
We can calculate Gibbs free energy (ΔG°) using the following expression.
ΔG° = -n.F.E°
where,
n are the moles of electrons transferred
F is Faraday's constant
ΔG° = - 2 mol × (96468 J/V.mol) × 4.40 V = -8.49 × 10⁵ J
Answer:
136
Explanation:
The Mass Number is the combination of the amount of Protons and Neutrons in an element, so if the total mass is 222, and the amount of protons is 86, then you can do 86 + x = 222 to find that x is equal to 136
For sig figs, you count the total number of numbers that aren’t 0, you only count 0 if they are after a decimal point. since there is not a decimal point, there are 2 significant figures, answer A
Answer:
Br
Explanation:
because bromine is more reactive as reactivity increases on moving from left to right in p-block. hope this make sense :)