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3 years ago

What was the result of the atomic theory?

1 answer:

5 0

Dalton's atomic theory proposed that all matter was composed of atoms, indivisible and indestructible building blocks. ... Dalton also postulated that chemical reactions resulted in the rearrangement of the reacting atoms.

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The work function for metallic potassium is 2.3 eV. Calculate the velocity in km/s for electrons ejected from a metallic potassi

mote1985 [20]

Answer:

932.44 km/s

Explanation:

Given that:

The work function of the magnesium = 2.3 eV

Energy in eV can be converted to energy in J as:

1 eV = 1.6022 × 10⁻¹⁹ J

So, work function = $2.3\times 1.6022\times 10^{-19}\ J=3.68506\times 10^{-19}\ J$

Using the equation for photoelectric effect as:

$E=\psi _0+\frac {1}{2}\times m\times v^2$

Also, $E=\frac {h\times c}{\lambda}$

Applying the equation as:

$\frac {h\times c}{\lambda}=\psi _0+\frac {1}{2}\times m\times v^2$

Where,

h is Plank's constant having value $6.626\times 10^{-34}\ Js$

c is the speed of light having value $3\times 10^8\ m/s$

m is the mass of electron having value $9.11\times 10^{-31}\ kg$

$\lambda$ is the wavelength of the light being bombarded

$\psi _0=Work\ function$

v is the velocity of electron

Given, $\lambda=260\ nm=260\times 10^{-9}\ m$

Thus, applying values as:

$\frac{6.626\times 10^{-34}\times 3\times 10^8}{260\times 10^{-9}}=3.68506\times 10^{-19}+\frac{1}{2}\times 9.11\times 10^{-31}\times v^2$

$3.68506\times \:10^{-19}+\frac{1}{2}\times \:9.11\times \:10^{-31}v^2=\frac{6.626\times \:10^{-34}\times \:3\times \:10^8}{260\times \:10^{-9}}$

$\frac{1}{2}\times 9.11\times 10^{-31}\times v^2=7.64538\times 10^{-19}-3.68506\times 10^{-19}$

$\frac{1}{2}\times 9.11\times 10^{-31}\times v^2=3.96032462\times 10^{-19}$

$v^2=0.869446\times 10^{12}$

v = 9.3244 × 10⁵ m/s

Also, 1 m = 0.001 km

So, v = 932.44 km/s

5 0

2 years ago

The reaction 2X →products is a second-order reaction, and the rate constant is 8.8 × 10−3 1/M·s. If the initial concentration of

tangare [24]

Answer is: A) 124 s.
c₀ = 3 mol/L.
c₁ = 0,700 mol/L.
k = 8,8·10⁻³ 1/M·s.
Integrated second order rate law is: 1/c₁ = 1/c₀ + k·t.
k·t = 1/0,700 - 1/3.
0,0088·t = 1,095.
t = 1,095 ÷ 0,0088.
t = 124 s.
c₀ - initial concentration.
c₁ - concentration at a particular time.
k - the rate constant.
t - time.

7 0

3 years ago

Two tons of water is pumped into a tank 15 ft. High in 5 minutes. Determine the power output of the pump. (Note: One ton is equa

Semmy [17]

Answer:

200 lb•ft/s

Explanation:

From the question given above, the following data were obtained:

Force (F) = 2 tons

Time (t) = 5 mins

Height (h) = 15 ft

Power (P) =?

Next, we shall convert 2 tons to pound. This can be obtained as follow:

1 ton = 2000 lb

Therefore,

2 tons = 2 × 2000

2 tons = 4000 lb

Next, we shall convert 5 mins to seconds. This can be obtained as follow:

1 min = 60 s

Therefore,

5 mins = 5 × 60

5 mins = 300 s

Finally, we shall determine the power of the pump. This can be obtained as follow:

Force (F) = 4000 lb

Time (t) = 300 s

Height (h) = 15 ft

Power (P) =?

P = F × h / t

P = 4000 × 15 / 300

P = 60000 / 300

P = 200 lb•ft/s

Thus, the power of the pump is 200 lb•ft/s

5 0

2 years ago

Identify the compounds that are soluble in both water and hexane.

dlinn [17]

Answer:

The compound which are boh soluble in water and hexane is

B. Ethanol and 1-propanol

Explanation:

The compounds ethanol and 1-propanol are soluble in both hexane and water.

It is soluble in water as both consists of polar end due to hydrogen bonding present in the -OH functional group.

and both are soluble in hexane as they contain a non polar end and the alliphatic hydrocarbon chain in them.

The solubility of alcohols varies in increasing order as the hydrocarbon chain increases. And becaue of this it becomes more non polar.

Non polar properties decreases for branched molecules.

so, the correct option is ethanol and 1-propanol.

3 0

3 years ago

Whoever awser correct I will give you Brainly

vivado [14]

Answer:

Option A.

2Na + 2H2O —> 2NaOH + H2

Explanation:

To know which option is correct, we shall do a head count of the number of atoms present on both side to see which of them is balanced. This is illustrated below below:

For Option A:

2Na + 2H2O —> 2NaOH + H2

Reactant >>>>>>> Product

2 Na >>>>>>>>>>> 2 Na

4 H >>>>>>>>>>>> 4 H

2 O >>>>>>>>>>>> 2 O

Thus, the above equation is balanced.

For Option B:

2Na + 2H2O —> NaOH + H2

Reactant >>>>>>> Product

2 Na >>>>>>>>>>> 1 Na

4 H >>>>>>>>>>>> 3 H

2 O >>>>>>>>>>>> 1 O

Thus, the above equation is not balanced.

For Option C:

2Na + H2O —> 2NaOH + H2

Reactant >>>>>>> Product

2 Na >>>>>>>>>>> 2 Na

2 H >>>>>>>>>>>> 4 H

1 O >>>>>>>>>>>> 2 O

Thus, the above equation is not balanced.

For Option D:

Na + 2H2O —> NaOH + 2H2

Reactant >>>>>>> Product

1 Na >>>>>>>>>>> 1 Na

4 H >>>>>>>>>>>> 5 H

2 O >>>>>>>>>>>> 1 O

Thus, the above equation is not balanced.

From the illustrations made above, only option A is balanced.

7 0

2 years ago