All categories

3 years ago

1. What is a forensic palyn ologist?

Chemistry

1 answer:

NemiM [27]3 years ago

5 0

Answer:

A forensic palynologist is a spore and pollen expert that helps solve crimes.

The case that Mildenhall worked on was about a murder that involved a prostitute. The police couldn’t find a trace to help solve the case, so they called Mildenhall to help with pollen clues. He was able to find trace evidence in the pollen, which helped police connect the victim to a gang hangout by the crime scene.

A forensic palynologist can help with a criminal investigation by comparing pollen from the suspect and the victim using a comparison microscope to determine if the pollen matches.

The challenges of using a forensic palynologist in a criminal investigation are that judges and juries may have a hard time understanding palynologists.

Explanation:

You might be interested in

Why do planets rotate around our sun

Andrei [34K]

Answer:

the most basic way i can put it is..

Explanation:

the planets rotate around the sun is because the gravity of the sun keeps them in their orbits. if the sun wasnt there, the earth would literally just travel in a straight line. but the gravity of the sun alters its course, making it travel around the sun.

6 0

3 years ago

Part C Number of molecules in 8.437x10-2 mol C6H6

N76 [4]

Answer:

There are $5.08\times 10^{22}\ \text{molecules of}\ C_6H_6$

Explanation:

In this problem, we need to find the number of molecules in $8.437\times 10^{-2}$ mol of $C_6H_6$ .

The molar mass of $C_6H_6$ is $6\times 12+1\times 6=78\ g/mol$

No of moles = mass/molar mass

We can find mass from above formula.

$m=n\times M\\\\m=8.437\times 10^{-2}\ mol\times 78\ g/mol\\\\m=6.58\ g$

Also,

No of moles = no of molecules/Avogadro number

$N=n\times N_A\\\\N=8.437\times 10^{-2}\times 6.023\times 10^{23}\\\\N=5.08\times 10^{22}\ \text{molecules}$

Hence, there are $5.08\times 10^{22}\ \text{molecules of}\ C_6H_6$

5 0

3 years ago

(a) What is the basis of the approximation that avoids using the quadratic formula to find an equilibrium concentration?

rusak2 [61]

The approximation is valid because is very small.

Calculation of concentration:

Since

0.85 M 0 0

(0.85-x)M x x

Now the value of x should be

x = 0.0000229

So based on this, the above concentration should be determined.

Now you will solve using the quadratic formula instead of iterations, to show that the same value of x is obtained either way. using the quadratic equation to calculate [h3o+] in 0.00250 m hno2, what are the values of a, b, c and x , where a, b, and c are the coefficients in the quadratic equation ax2+bx+c=0, and x is [h3o+]? recall that ka=4.5×10−4 .

a: 1

b: 4.5x10⁻⁴

c: 1.125x10⁻⁶

[H₃O⁺] = 0.000859M

As HNO₂ is a weak acid, its equilibrium in water is:

HNO₂(aq) + H₂O(l) ⇄ H₃O⁺(aq) + NO₂⁻(aq)

Equilibrium constant, ka, is defined as:

ka = 4.5x10⁻⁴ = [H₃O⁺] [NO₂⁻] / [HNO₂] (1)

Equilibrium concentration of each specie are:

[HNO₂] = 0.00250M - x

[H₃O⁺] = x

[NO₂⁻] = x

Replacing in (1):

4.5x10⁻⁴ = x × x / 0.00250M - x

1.125x10⁻⁶ - 4.5x10⁻⁴x = x²

0 = x² + 4.5x10⁻⁴x - 1.125x10⁻⁶

As the quadratic equation is ax² + bx + c = 0

Coefficients are:

a: 1

b: 4.5x10⁻⁴

c: 1.125x10⁻⁶

Now, solving quadratic equation:

x = -0.0013 → False answer, there is no negative concentrations.

x = 0.000859

As [H₃O⁺] = x; [H₃O⁺] = 0.000859M

To know more about Equilibrium constant

brainly.com/question/19340344

#SPJ4

7 0

2 years ago

The table below shows the role of different substances during photosynthesis.

RoseWind [281]

A I think I could be wrong I’m not good at this

6 0

3 years ago

Read 2 more answers

Calculate the solubility of hydrogen in water at an atmospheric pressure of 0.380 atm (a typical value at high altitude).

Pani-rosa [81]

The question is incomplete, here is the complete question:

Calculate the solubility of hydrogen in water at an atmospheric pressure of 0.380 atm (a typical value at high altitude).

Atmospheric Gas Mole Fraction kH mol/(L*atm)

$N_2$ $7.81\times 10^{-1}$ $6.70\times 10^{-4}$

$O_2$ $2.10\times 10^{-1}$ $1.30\times 10^{-3}$

Ar $9.34\times 10^{-3}$ $1.40\times 10^{-3}$

$CO_2$ $3.33\times 10^{-4}$ $3.50\times 10^{-2}$

$CH_4$ $2.00\times 10^{-6}$ $1.40\times 10^{-3}$

$H_2$ $5.00\times 10^{-7}$ $7.80\times 10^{-4}$

Answer: The solubility of hydrogen gas in water at given atmospheric pressure is $1.48\times 10^{-10}M$

Explanation:

To calculate the partial pressure of hydrogen gas, we use the equation given by Raoult's law, which is:

$p_{\text{hydrogen gas}}=p_T\times \chi_{\text{hydrogen gas}}$

where,

$p_A$ = partial pressure of hydrogen gas = ?

$p_T$ = total pressure = 0.380 atm

$\chi_A$ = mole fraction of hydrogen gas = $5.00\times 10^{-7}$

Putting values in above equation, we get:

$p_{\text{hydrogen gas}}=0.380\times 5.00\times 10^{-7}\\\\p_{\text{hydrogen gas}}=1.9\times 10^{-7}atm$

To calculate the molar solubility, we use the equation given by Henry's law, which is:

$C_{H_2}=K_H\times p_{H_2}$

where,

$K_H$ = Henry's constant = $7.80\times 10^{-4}mol/L.atm$

$p_{H_2}$ = partial pressure of hydrogen gas = $1.9\times 10^{-7}atm$

Putting values in above equation, we get:

$C_{H_2}=7.80\times 10^{-4}mol/L.atm\times 1.9\times 10^{-7}atm\\\\C_{CO_2}=1.48\times 10^{-10}M$

Hence, the solubility of hydrogen gas in water at given atmospheric pressure is $1.48\times 10^{-10}M$

4 0

3 years ago