plz answer question (ii)

Answer:

hope this helps.answer is in the picture

Answer:

The wavelength of the incoming photon is 172.8 nm

Explanation:

The wavelength of the incoming photon can be calculated with the photoelectric equation:

[tex] KE = h\frac{c}{\lambda_{p}} - \phi [/tex]   (1)

Where:

KE: is the kinetic energy of the electron

h: is Planck's constant = 6.62x10⁻³⁴ J.s  

c: is the speed of light = 3.00x10⁸ m/s

[tex]\lambda_{p}[/tex]: is the wavelength of the photon =?  

Φ: is the work function of the surface (Iron) = 4.5 eV        

The kinetic energy of the electron is given by:

[tex] KE = \frac{p^{2}}{2m} = \frac{(\frac{h}{\lambda_{e}})^{2}}{2m} [/tex]  (2)

Where:  

p: is the linear momentum = h/λ

m: is the electron's mass = 9.1x10⁻³¹ kg

[tex]\lambda_{e}[/tex]: is the wavelength of the electron = 0.75 nm = 0.75x10⁻⁹ m

Hence, the wavelength of the photon is:

[tex] \frac{(\frac{h}{\lambda_{e}})^{2}}{2m} = h\frac{c}{\lambda_{p}} - \phi [/tex]

[tex]\lambda_{p} = \frac{hc}{\frac{h^{2}}{2m\lambda_{e}^{2}} + \phi} = \frac{6.62 \cdot 10^{-34} J.s*3.00\cdot 10^{8} m/s}{\frac{(6.62 \cdot 10^{-34} J.s)^{2}}{2*9.1 \cdot 10^{-31} kg*(0.75 \cdot 10^{-9} m)^{2}} + 4.5 eV*\frac{1.602 \cdot 10^{-19} J}{1 eV}} = 1.728 \cdot 10^{-7} m = 172.8 nm[/tex]      

Therefore, the wavelength of the incoming photon is 172.8 nm.

I hope it helps you!        

Answer: i Choose the sun

because it has mass

Explanation: matter is anything that has mass and occupies space / Volume

and the sun has mass though it is not a solid one, and is made up of matter

HOPE THIS HELPSS!!!!

Answer:

Phase C - Liquid State

Phase E - Gaseous State

Explanation:

Usually, in phases of water, we have the following;

When temperature is less than zero, it is said to be in its solid phase as ice.

When temperature is between 0 to 100, we can say it is in the liquid phase as water.

When temperature is above 100°C, It is said to be in the gaseous phase as vapour.

From the diagram;

Phase C is the only liquid state because it falls between temperature of 0°C and 100°

Also, only phase E is in the gaseous phase because the temperature is above 100°C.

Answer:

net ionic equation

[tex]\boxed{ SO_4{}^{2-} {}_{(aq.)} + Ba^{2+} {}_{(aq.)} \rightarrow BaSO_4 {}_{(s)}} [/tex]

Answer:

0.32 liters/mole cm.

Explanation:

According to Beer Lambert's law;

A= εcl

ε = molar absorptivity

c= concentration

l= path length

A= 4.17*10^4 × 7.68*10^-6 × 1

A= 0.32 liters/mole cm.

Answer:

Option C. 11

Explanation:

We'll begin by calculating the concentration of the hydroxide ion [OH¯] in the solution. This can be obtained as follow:

In solution, KOH will dissociate as follow:

KOH (aq) <=> K⁺(aq) + OH¯(aq)

From the balanced equation above,

1 mole of KOH reacted to produce 1 mole of OH¯.

Therefore, 1×10¯³ M KOH will also react to produce 1×10¯³ M OH¯.

Thus, the concentration of hydroxide ion [OH¯] in the solution is 1×10¯³ M

Next, we shall determine the pOH of the solution. This can be obtained as follow:

Concentration of hydroxide ion [OH¯] = 1×10¯³ M

pOH =?

pOH = –Log [OH¯]

pOH = –Log 1×10¯³

pOH = 3

Finally, we shall determine the pH of the solution. This can be obtained as follow:

pOH = 3

pH =?

pH + pOH = 14

pH + 3 = 14

Collect like terms

pH = 14 – 3

pH = 11

Answer:

I think it is C

Explanation:

Hope this helps!! :)

If I'm wrong, then greatest apologies

Answer:

I don't know yr language

nobody can say it is uncertain but in my opinion it will grow quickly in the next 10 years

Respuesta:

4.26 M; 12.8 N

Explicación:

Primer paso: Calcular la concentración volumétrica (Cv)

Usaremos la siguiente expression.

Cv = Cg × ρ

Cv = 30 g%g × 1.39 g/mL = 41.7 g%mL

Segundo paso: Calcular la molaridad

La concentración volumetrica es 41.7 g%mL, es decir, hay 41.7 gramos de soluto cada 100 mL de solución. Usaremos la siguiente fórmula para molaridad.

M = masa de soluto / masa molar de soluto × litros de solución

M = 41.7 g / 97.99 g/mol × 0.1 L = 4.26 M

Tercer paso: Calcular la normalidad

Usaremos la siguiente fórmula.

N = M × Z

donde Z para un ácido es igual al número de protones.

N = M × Z

N = 4.26 mol/L × 3 eq/mol = 12.8 N

Answer:

TIMED HELP ASAP

19.11 g of MgSO₄ is placed into 100.0 mL of water. The water's temperature increases by 6.70°C. Calculate ∆H, in kJ/mol, for the dissolution of MgSO₄. (The specific heat of water is 4.184 J/g･°C and the density of the water is 1.00 g/mL). You can assume that the specific heat of the solution is the same as that of water.

Answer:

-21.03 kJ/mol

Explanation:

∆H is enthalpy. Enthalpy is the total heat content of a system.

So we can establish that ∆H = q (heat)

The formula for heat (q)

q = cm∆T

c = specific heat capacity

m = mass of substance

∆T= change of temperature

Since we are calculating the enthalpy of the SOLUTION. We must account for both the mass of water and the mass of MgSO₄ in our q formula.

All you gotta do is plug and chug at this stage.

∆H = q     = cm∆T = (4.184)(19.11+100.0)(6.70) = 3338.986808 Joules

We have now calculated the heat (aka enthalpy) of the solution.

BUT

Remember! The problem asked for enthalpy in kj....

Use this conversion factor.

1000 J = 1 kJ

3338.986808 Joules * 1kJ/1000 J = 3.338986808 kJ

We were asked to find ∆H for the dissolution of MgSO4  in units of kj/mol so we are not finished.

Take the grams of MgSO4 in the problem  and convert it into moles using its molar mass.

MgSO4 molar mass = 120.3676 g

1 mol = 120.3676 g MgSO4   <---- Use this as a conversion factor

19.11 g MgSO4 * 1 mol MgSO4/120.3676 g = 0.15876365 mol MgSO4

Now that you've calculated the moles of MgSO4 in this solution. You can divide your heat by it.

q dissolution = 3.338.986808 kJ/ 0.15876365 mol =  21.03 kj/mol

Note that the problem tells us that the temperature of water increases.

This means that the water is experiencing an endothermic process (heat is being absorbed from MgSO4) . Mathematically, this would be indicated by a positive sign. ---> +q

We can assume MgSO4 is losing heat as it is placed into the water. It is experiencing an exothermic process (heat is being lost).  Mathematically, this would be indicated by a negative sign. ----> -q

So if we're calculating the enthalpy for the dissolution of MgSO₄ ....the value we've arrived at must be negative.

Answer

∆H = 21.03 kj/mol :)))))

I hope that helped...I feel like my explanation was a bit convoluted.

Answer:

a. H2O: dihydrogen monoxide

b. PCl5: Phosphorus pentachloride

c. SiF4: Silicon tetrafluoride

d. N20: dinitrogen oxide

Answer:

transition state is a point in which electrons been removed from the atom

Answer:

The highest energy structure in the reaction coordinate.

Explanation:

Answer:

Answer to the following question is as follows;

Explanation:

Alkynes' vapour pressure and normal boiling points are altered when chain length grows, since vapour pressure rises while boiling point falls.

Vapour pressure always include pressure entered by vapour with its condensed phase, pressure include molecules force of attraction include vapour

Answer:

oh it's easy

Explanation:

Take the hydrate

N

a

2

S

2

O

3

∙

5

H

2

O

. Are there ionic forces between the

N

a

+

and the

S

2

O

2

−

3

and ion-dipole forces between the cation/anions and the water?

Answer:

87059.50558 pa

Explanation:

Dalton's law of partial pressure states that Ptotal=P1 +P2+ P3

417mmHg + 150mmHg +86mmHg =653 mmHg

convert it to Pa, your answer is 87059.50558Pa.

I hope I'm of help to you

Answer:

No and Yes

Explanation:

it depends bc its an ionic compound, therefore can't conduct electricity when SOLID, BUT unless it DISSOLVES in water it can conduct

Answer:

c hierro

no se la otra sorry

Answer:

beryllium is the answer.

I hope this will help you

The question is incomplete, the complete question is;

.On heating 12.4 g of copper (II) carbonate in a crucible only 7.0g of copper (II) oxide was produced. What was the % yield of copper (II) oxide ? [Cu=64,C=12,O=16]

Answer:

87.5%

Explanation:

CuCO3 -------> CuO + CO2

Number of moles of CuCO3 = 12.4g/123.55 g/mol = 0.1 moles

Since the reaction is 1:1,

Mass of CuO produced = 0.1 moles × 80g/mol = 8 g

Hence,

% yield = actual yield/theoretical yield × 100

% yield = 7/8 × 100

% yield = 87.5%

Answer:

1. Absolute time, also known as Newtonian time is a time that exists independent of the observer of the time, and therefore, can only be expressed through mathematics

Absolute dating is a dating method that makes use of the radioactive property of matter and is determined through dating of radioactive isotopes present

Absolute time (dating) is found through radioactive dating

2. Radioactive isotopes are atoms that have the property of unstable proton neutron combination or excess energy nucleus. They can be fined as unstable element

3. A stabilized isotope are the decay product atoms of the element which are non radioactive.

4. The half life is the time it takes the original isotope to decay into the decay product

5. To determine the age of a rock, the proportion of the original isotope to the amount of decay product in the rock is compared

6. The isotope used to date organic materials is carbon-14

7. The isotope used to date rocks with comparable age to the Earth is Uranium-238 that has a half life of 4.468 billion years

8. The half life of carbon-14 is only 5,700 years while the age of a dinosaur is between 245 and 66 million years ago, and therefore, carbon is absent in most fossils

9. Uranium-238 is only found in igneous or volcanic rocks and not in metamorphic rocks, therefore, fossils  of dinosaur as well as other fossils that are buried in sedimentary materials, including sand and clay, cannot be determined by Uranium-238

Explanation:

Answer:

1.03 grams of hydrogen is produced from 12.5 g of Mg reacting with hydrochloric acid.

Explanation:

The balanced reaction is:

Mg+ 2 HCl → MgCl₂ + H₂

By stoichiometry of the reaction, the following amounts of moles of each compound participate in the reaction:

Being the molar mass of each compound:

By reaction stoichiometry, the following mass amounts of each compound participate in the reaction:

Then you can apply the following rule of three: if by stoichiometry 24.31 grams of Mg produces 2 grams of H₂, 12.5 grams of Mg produces how much mass of H₂?

[tex]mass of H_{2} =\frac{12.5 grams of Mg* 2 grams of H_{2}}{24.31 grams of Mg}[/tex]

mass of H₂= 1.03 grams

1.03 grams of hydrogen is produced from 12.5 g of Mg reacting with hydrochloric acid.

Answer:

the valence of S is -2. For FeS to be neutral the valence of Fe used must be +2

and since Iron (II) has its valency 2, FeS will be Iron (II) Sulfide.