Which question would most likely be studied by a chemist?

Suppose you are working with a NaOH stock solution but you need a solution with a lower concentration for your experiment. Calcu

Svet_ta [14]

Answer:

$V_1=23.3~mL$

Explanation:

In this case, we have a dilution problem. We have to remember that in the dilution procedure we go from a solution with higher concentration to a solution with lesser concentration. Therefore we have to start with the dilution equation:

$C_1*V_1=C_2*V_2$

Now we can identify the variables:

$C_1=~1.475_M$

$V_1=~?$

$C_2=~0.1374_M$

$V_2=~250.0~mL$

If we plug all the values into the equation:

$1.475_M*V_1=0.1374_M*250.0~mL$

And we solve for $V_1$ :

$V_1=\frac{0.1374_M*250.0~mL}{1.475_M}$

$V_1=23.3~mL$

I hope it helps!

8 0

3 years ago

When a hydrogen atom makes the transition from the second excited state to the ground state (at -13.6 eV) the energy of the phot

viktelen [127]

Answer : The energy of the photon emitted is, -12.1 eV

Explanation :

First we have to calculate the $'n^{th}'$ orbit of hydrogen atom.

Formula used :

$E_n=-13.6\times \frac{Z^2}{n^2}ev$

where,

$E_n$ = energy of $n^{th}$ orbit

n = number of orbit

Z = atomic number of hydrogen atom = 1

Energy of n = 1 in an hydrogen atom:

$E_1=-13.6\times \frac{1^2}{1^2}eV=-13.6eV$

Energy of n = 2 in an hydrogen atom:

$E_3=-13.6\times \frac{1^2}{3^2}eV=-1.51eV$

Energy change transition from n = 1 to n = 3 occurs.

Let energy change be E.

$E=E_-E_3=(-13.6eV)-(-1.51eV)=-12.1eV$

The negative sign indicates that energy of the photon emitted.

Thus, the energy of the photon emitted is, -12.1 eV

3 0

3 years ago

Which of the following is not an example of a polymer?

Nady [450]

I believe the correct answer from the choices listed above is the third option. It is amino acid that is not an example of a polymer. It <span> is a large molecule, or macromolecule, composed of many repeated subunits. Hope this answers the question.</span>

7 0

3 years ago

Gu

Andrei [34K]

According of Dalton's law of Partial pressure, the total pressure of a mixture of gases is the sum of the partial pressures of the individual vases in the mixture.

Hence;

The for hydrogen collected over water, we have a mixture of hydrogen gas and water vapour.

Total pressure = pressure of hydrogen gas + vapour pressure of water

Pressure of hydrogen gas = Total pressure - vapour pressure of water

Pressure of hydrogen gas = 636 mmHg - 28.3 mmHg

Pressure of hydrogen gas = 607.7 mmHg

7 0

3 years ago

A certain gas is present in a 15.0 LL cylinder at 2.0 atmatm pressure. If the pressure is increased to 4.0 atmatm the volume of

Helga [31]

Explanation:

According to Boyle's law, pressure of a gas is inversely proportional to its volume at constant temperature and moles.