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Hoochie [10]
3 years ago
14

A 25.0-mL sample containing Cu2+ gave an instrument signal of 25.2 units (corrected for a blank). When exactly 0.500 mL of 0.027

5 M Cu(NO3)2 was added to the solution, the signal increased to 45.1 units. Calculate the molar concentration of Cu2+ assuming that the signal was directly proportional to the analyte concentration. Skoog, Douglas A.. Principles of Instrumental Analysis (p. 20). Brooks Cole. Kindle Edition.
Chemistry
1 answer:
irga5000 [103]3 years ago
7 0

Answer:

The molar concentration of Cu²⁺ in the initial solution is 6.964x10⁻⁴ M.

Explanation:

The first step to solving this problem is calculating the number of moles of Cu(NO₃)₂ added to the solution:

C = \frac{n}{V} \\0.0275 = \frac{n}{0.0005} \\

n = 1.375x10⁻⁵ mol

The second step is relating the number of moles to the signal. We know the the n calculated before is equivalent to a signal increase of 19.9 units (45.1-25.2):

1.375x10⁻⁵ mol _________ 19.9 units

        x              _________  25.2 units

x = 1.741x10⁻⁵mol

Finally, we can calculate the Cu²⁺ concentration :

C = 1.741x10⁻⁵mol / 0.025 L

C = 6.964x10⁻⁴ M

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Free Energy
ratelena [41]

Answer:

a) galvanic cell

b)electrolytic cell

c) i) K=6.27x10'34

ΔG°=198790 J

ii) K=3.58x10'-34

ΔG°= 191070 J

d) E°=0.278 v

ΔG°= -26827 J

Explanation:

a) There are two kinds of an electrochemical cell, the first is called "galvanic cells", and the second "electrolytic cell".

The fuel cells are capable of produce electric energy through chemical reactions. These reactions are often spontaneous. So, the galvanic cell has a negative value for Gibbs free energy.

b) The electrolytic cell increases the value of Gibbs energy, to positive values, due to the reactions are not spontaneous.

c) i) look image attached

ii) k = look image attached

ΔG° = -nFE° = - 6 X 95500 J/vmole x (-0.33 v)

ΔG° =-191070

d) E°= 0.0592 v/n x lg K

E°= 0.0592V / 1 X log 5.0X10'4

E°= 0.278 v

ΔG° = -nFE° = -1 x 96500 J/ vmole x 0.278v

ΔG° = -26827 J

5 0
3 years ago
HeeeeeeeeeeeelllllllllllllllllllllllpppppppppppppppppppppppppppppFind the statement about Fusion that is false.
Pie

Fusion releases less energy than fission

fusion most commonly combines heavy isotopes of hydrogen into helium.

Explanation:

Nuclear fusion is a form of reaction that involves the combination of two light nuclei to form one that is heavier in mass.

The other form is nuclear fission which is the splitting of heavier nuclei either spontaneously or when bombarded with other nuclei.

  • Nuclear fusion reactions in the core of stars powers the universe.
  • The reactions produces a huge amount of energy of a greater and massive order than fission reaction.
  • Small nuclei are involved in nuclear fusion and not the large ones.
  • Nuclear fusion degenerates into series of chain reactions that are extremely difficult to control.

learn more;

Nuclear reactions brainly.com/question/10094982

#learnwithBainly

3 0
3 years ago
Write the chemichal name of each of the chemichal formula. 1)Pbo2,2)PbO
marishachu [46]

Answer:

Explanation:

1. Lead (IV) Oxide

2. Lead (II) Oxide

4 0
2 years ago
Which statements about allosteric enzymes are true?
Ainat [17]

Answer:

1,2 and 4 are correct

Explanation:

Enzymes that show cooperativity are defined as Allosteric enzymes. This cooperativity is of several types.

1) homotropic/homoallestery - positive cooperation

2) heterotropic/heteroallestery - negative cooperation

Activity of allosteric enzymes is regulated by other molecules (effector molecules)

Hence, statement 1 and 2 are correct.

Binding curve of allosteric enzymes:

For cooperative binding, binding curve is Sigmoidal curve

For non cooperative binding, binding curve is Hyperboilc curve.

Hence, statement 3 is wrong.

Allosteric enzymes have multiple active sites.

Allosteric enzymes are often multi sub unit proteins.

Hence, statement 4 is correct.

4 0
3 years ago
When warm air is forced upward along a cold front what might happen?
mote1985 [20]

Answer: With the cold front, warm air is rapidly forced upward (like the shavings) in advance of the actual front (the “cutter”), creating towering cumulus clouds, some hard showers and quite possibly a few gusty thunderstorms followed by a push of cooler and drier air in its wake.

Explanation:

8 0
2 years ago
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