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3 years ago

What story does Ms. McDermid share about maggots helping identify a dead man?

Chemistry

1 answer:

RSB [31]3 years ago

7 0

Answer:

The maggots had traces of this man in them and the entomologists found out who he was just by using the DNA in the maggots.

Explanation:

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An experiment requires 0.52 M NH3(aq). The stockroom manager estimates that 15 L of the base is needed. What volume of 15 M NH3(

Bingel [31]

Answer: 0.52 L of 15 M $NH_3(aq)$ will be used to prepare this amount of 0.52 M base.

Explanation:

But on diluting the number of moles remain same and thus we can use molarity equation.

$C_1V_1(stock)=C_2V_2$ (to be prepared)

where,

$C_1$ =concentration of stock solution = 15 M

$V_1$ = volume of stock solution = ?

$C_2$ = concentration of solution to be prepared = 0.52 M

$V_2$ = volume of solution to be prepared = 15 L

$15\times V_1=0.52\times 15$

$V_1=0.52L$

Thus 0.52 L of 15 M $NH_3(aq)$ will be used to prepare this amount of 0.52 M base

8 0

3 years ago

Two voltaic cells are to be joined so that one will run the other as an electrolytic cell. In the first cell, one half-cell has

vladimir1956 [14]

Au/Cr cell will run as a voltaic cell and Co/Zn cell will run as an electrolytic cell.

<h3>What is an electrolytic cell?</h3>

An electrolytic cell that uses electrical energy to enable a non-spontaneous redox reaction is known as an electrolytic cell.

Certain chemicals can be electrolyzed using electrolytic cells, which are electrochemical cells.

For example, water can be electrolyzed to create gaseous oxygen and gaseous hydrogen with the use of an electrolytic cell.

The following are the three essential parts of electrolytic cells:

Cathode (which is negatively charged for electrolytic cells)

Anode (which is positively charged for electrolytic cells)

Electrolyte

The reactions for each half cell is given by

$Au^{3+}(aq) + 3e^- \rightleftharpoons Au(s)$ ; E° = 1.50 V

$Cr^{3+}(aq) + 3e^- \rightleftharpoons Cr(s)$ ; E° = –0.74 V

$Co^{2+}(aq) + 2e^- \rightleftharpoons Co(s)$ ; E° = –0.28 V

$Zn^{2+}(aq) + 2e^- \rightleftharpoons Zn(s)$ ; E° = –0.76 V

When the Au/Cr cell will run as a voltaic cell and Co/Zn cell will run as an electrolytic cell, the a difference in the voltages is produced

$E^o_{series} = E^o_{Au/Cr} - E^o_{Co/Zn}$ = 2.24 V – 0.48 V = 1.76 V

Learn more about electrolytic cell:

brainly.com/question/19854746

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7 0

1 year ago

For which of the following reactions is S° > 0.

lisabon 2012 [21]

The entropy of the given reactions increases (S° > 0):

2C2H6(g) + 7O2(g) ----> 4CO2(g) + 6H2O(g) ---> S° > 0.
NH4Cl(s) ----> NH3(g) + HCl(g) ---> S° > 0.

<h3>What is entropy?</h3>

Entropy measure how disordered a system is. It a measure of how dispersed or random the total energy of a system is. The symbol for entropy is S.

A system in which entropy increases is one in which S° > 0.

The entropy of a system decreases when S° < 0.

Entropy of a system increases (S° > 0) if any change results in an increase in temperature, increase in number of molecules, or an increase in volume.

Considering the given systems, the entropy changes is as follows:

2C2H6(g) + 7O2(g) ----> 4CO2(g) + 6H2O(g) ---> S° > 0.
2CO2(g) + N2(g) ---->2CO(g) + 2NO(g) --> no change
2N2(g) + O2(g) -----> 2N2O(g) ---> decreases
S (s,rhombic) + 2CO(g) ----> SO2(g) + 2C (s,graphite) ---> no change
NH4Cl(s) ----> NH3(g) + HCl(g) ---> S° > 0.

In conclusion, an increase in volume and moles of substances results in entropy increase.

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8 0

2 years ago

How does a diaphragm help in viewing the specimen in a microscope

Keith_Richards [23]

Answer:

Diaphragm controls the amount of light reaching the specimen. It is located above the condenser and below the stage. Most high quality microscopes include an Abbe condenser with an iris diaphragm. Combined, they control both the focus and quantity of light applied to the specimen.

4 0

3 years ago

Applying the rules of significant figures, which of the following would be the correct value for the density of a substance whic

lilavasa [31]

16 g/ml

<h3>Further explanation</h3>

Given

mass = 32.40 g

volume = 2.0mL

Required

Density

Solution

Density is a quantity derived from the mass and volume

Density is the ratio of mass per unit volume

Density formula:

$\large {\boxed {\bold {\rho ~ = ~ \frac {m} {V}}}}$

ρ = density

m = mass

v = volume

Input the value :

ρ = 32.40 g / 2.0 ml

ρ = 16.2 g/ml

Rules for division: The least number of significant figures in the problem determines the number of significant figures in the answer.

32.40 = 4 sig.fig

2.0 = 2 sig fig

The answer must be 2 sig fig

So the answer = 16 g/ml

6 0

3 years ago