An electron is on a -2.5 eV energy level. The electron is struck by a 2.5 eV photon. What will most likely happen?

A 0.20 mol sample of MgCl2(s) and a 0.10 mol sample of KCl(s) are dissolved in water and diluted to 500 mL. What is the concentr

igor_vitrenko [27]

Answer:

1 M

Explanation:

Magnesium chloride will furnish chloride ions as:

$MgCl_2\rightarrow Mg^{2+}+2Cl^-$

Given :

Moles of magnesium chloride = 0.20 mol

Thus, moles of chlorine furnished by magnesium chloride is twice the moles of magnesium chloride as shown below:

$Moles =2\times 0.20\ moles$

Moles of chloride ions by magnesium chloride = 0.40 moles

Potassium chloride will furnish chloride ions as:

$KCl\rightarrow K^{+}+Cl^-$

Given :

Moles of potassium chloride = 0.10 moles

Thus, moles of chlorine furnished by potassium chloride is same as the moles of potassium chloride as shown below:

Moles of chloride ions by potassium chloride = 0.10 moles

Total moles = 0.40 + 0.10 moles = 0.50 moles

Given, Volume = 500 mL = 0.5 L (1 mL = 10⁻³ L)

Concentration of chloride ions is:

$Molarity=\frac{Moles\ of\ solute}{Volume\ of\ the\ solution}$

$Molarity_{Cl^-}=\frac{0.50}{0.5}$

The final concentration of chloride anion = 1 M

8 0

2 years ago

Why the gross reading is needed when doing the titration?

aleksklad [387]

Answer:

The answer is below

Explanation:

Because various factors can affect the actual value of the titration outcome. Some of these factors can range from errors from a researcher also known as human error, misreading the quantities, researcher's perception of the color, or wrong procedure in carrying out the experimentation.

Hence, in order to avoid such error, a researcher needs to be thorough during the process of experimentation, and using gross reading can help to avoid these errors when the titre value is eventually determined.

7 0

2 years ago

For some hypothetical metal, the equilibrium number of vacancies at 600°C is 1 × 1025 m-3. If the density and atomic weight of t

makvit [3.9K]

Answer:

$\frac{N_{v}}{N}=1.92*10^{-4}$

Explanation:

First of all we need to find the amount of atoms per volume (m³). We can do this using the density and the molar mass.

$7.40 \frac{g}{cm^{3}}*\frac{1mol}{85.5 g}*\frac{6.023*10^{23}atoms}{1mol}*\frac{1000000 cm^{3}}{1m^{3}}=5.21*10^{28}\frac{atoms}{m^{3}}$

Now, the fraction of vacancies is equal to the N(v)/N ratio.

N(v) is the number of vacancies $1*10^{25}m^{-3}$
N is the number of atoms per volume calculated above.

Therefore:

The fraction of vacancies at 600 °C will be:

$\frac{N_{v}}{N}=\frac{1*10^{25}}{5.21*10^{28}}$

$\frac{N_{v}}{N}=1.92*10^{-4}$

I hope it helps you!

7 0

2 years ago

Use the following half-reactions to construct a voltaic cell:

velikii [3]

Answer: The correct answer is $3Ag^+(aq.)+Cr(s)\rightarrow 3Ag(s)+Cr^{3+}(aq.);E^o_{cell}=+1.53V$

Explanation:

We are given:

$Cr^{3+}(aq.)+3e^-\rightarrow Cr(s);E^o=-0.73V\\\\Ag^+(aq.)+e^-\rightarrow Ag(s);E^o=+0.80V$

The substance having highest positive $E^o$ potential will always get reduced and will undergo reduction reaction. Here, silver will always undergo reduction reaction will get reduced.

Chromium will undergo oxidation reaction and will get oxidized.

The half reactions for the above cell is:

Oxidation half reaction: $Cr(s)\rightarrow Cr^{3+}+3e^-;E^o_{Cr^{3+}/Cr}=-0.73V$

Reduction half reaction: $Ag^{+}+e^-\rightarrow Ag(s);E^o_{Ag^{+}/Ag}=0.80V$ ( × 3)

Net equation: $3Ag^+(aq.)+Cr(s)\rightarrow 3Ag(s)+Cr^{3+}(aq.)$

Oxidation reaction occurs at anode and reduction reaction occurs at cathode.

To calculate the $E^o_{cell}$ of the reaction, we use the equation:

$E^o_{cell}=E^o_{cathode}-E^o_{anode}$

Putting values in above equation, we get:

$E^o_{cell}=0.80-(-0.73)=1.53V$

Hence, the correct answer is $3Ag^+(aq.)+Cr(s)\rightarrow 3Ag(s)+Cr^{3+}(aq.);E^o_{cell}=+1.53V$

4 0

2 years ago

When the Modern Museum of Art separated its consumers by whether they were culture-oriented or outdoor-oriented for its new exhi

madam [21]

Answer:

A. psychographic lifestyle segmentation

Explanation:

Psychographic lifestyle segmentation -

It refers to the distribution or classification method , where the consumers of a particular goods and services are classified into particular groups , depending on the psychological characteristics of the consumers , is referred to as psychographic lifestyle segmentation .

The segmentation take care of the consumers celief , priority , va;ues , decision - making process , lifestyle .

The method enables to market the goods and services in a better manner , nd increases the profit of the company .

Hence , from the given scenario of the question ,

The correct option is A. psychographic lifestyle segmentation .

8 0

2 years ago