If 225 grams of propane are burned in the presence of 125 grams of oxygen, how many grams of water should be expected?

How much energy would be released as an electron moved from the n=4 to the n=3 energy level?

Thepotemich [5.8K]

The energy released when electron move from n=4 to n=3 is 0.66 eV

We know that in an atom energy of nth state is

$E_n = -13.6/n^{2}$ eV

where n is the energy level

Therefore,

$E_4 = -13.6/4^{2} \\E_3 = -13.6/3^{2}$

Thus, $E_4$ = -0.85eV

$E_3$ = -1.51eV

Therefore, total mount of energy released in moving electron from n=4 to n=3 is given by -

$E_4 -E_3$

= -0.85 - ( -1.51)

= 0.66eV

To know more about energy released in electron transition

brainly.com/question/8384785

#SPJ4

8 0

2 years ago

Uranium, an important component of both nuclear weapons and nuclearreactors, has two major isotopes, U-238, which has a half-lif

elixir [45]

Answer:

Hello your question is poorly written below is the well written question

Uranium, an important component of both nuclear weapons and nuclear reactors, has two major isotopes, U-238, which has a half-life of approximately 4.5 billion years, and U-235, which has a half-life of approximately 700 million years. Both were present in equal amounts at the time of the creation of the Earth, 4.5 billion years ago. How many years after the creation of the Earth had the amount of radiation from uranium decayed to half the amount present at the time of the creation of the Earth

Answer : 140 billion years

Explanation:

Given that :

U-238 h1/2 = 4.5 billion years

U-235 h1/2 = 700 million years

At the beginning both Isotopes where present in equal amount

Determine the T years before the amount of Uranium decays to Half

T = ? N'2 = N1 / 2

we know that N = No ( 1/2 )^h where h = time / half-life time

attached below is the detailed solution of the given problem

6 0

2 years ago

Heavy nuclides with too few neutrons to be in the band of stability are most likely to decay by what mode?

Margarita [4]

Answer:

Positron emission

Explanation:

Positron emission involves the conversion of a proton to a neutron. This process increases the mass number of the daughter nucleus by 1 while its atomic number remains the same. The new neutron increases the number of neutrons present in the daughter nucleus hence the process increases the N/P ratio.

A positron is usually ejected in the process together with an anti-neutrino to balance the spins.

6 0

3 years ago

Aspirin sun thesis Green Chemistry and Assime the aspirin is prepared by the following reaction and that 10.09. of salicylic aci

klemol [59]

Answer: The percentage yield of aspirin is 38.02 %.

Explanation:

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$ .....(1)

For salicylic acid:

Given mass of salicylic acid $(C_7H_6O_3)$ = 10.09 g

Molar mass of salicylic acid $(C_7H_6O_3)$ = 138.12 g/mol

Putting values in equation 1, we get:

$\text{Moles of salicylic acid}=\frac{10.09g}{138.12g/mol}=0.0730mol$

The chemical equation for the formation of aspirin follows:

$C_7H_6O_3+C_4H_6O_3\rightarrow C_9H_8O_4+CH_3COOH$

As, acetic anhydride is present in excess. So, it is considered as an excess reagent.

Thus, salicylic acid is a limiting reagent because it limits the formation of products.

By Stoichiometry of the reaction:

1 mole of salicylic acid produces 1 mole of aspirin.

So, 0.0730 moles of salicylic acid will produce = $\frac{1}{1}\times 0.0730=0.0730mol$ of aspirin

Now, calculating the mass of aspirin from equation 1, we get:

Molar mass of aspirin = 180.16 g/mol

Moles of aspirin = 0.073 moles

Putting values in equation 1, we get:

$0.073mol=\frac{\text{Mass of aspirin}}{180.16g/mol}\\\\\text{Mass of aspirin}=13.15g$

To calculate the percentage yield of aspirin, we use the equation:

$\%\text{ yield}=\frac{\text{Experimental yield}}{\text{Theoretical yield}}\times 100$

Experimental yield of aspirin = 5.0 g

Theoretical yield of aspirin = 13.15 g

Putting values in above equation, we get:

$\%\text{ yield of aspirin}=\frac{5.0g}{13.15g}\times 100\\\\\% \text{yield of aspirin}=38.02\%$

Hence, the percent yield of aspirin is 38.01 %.

6 0

3 years ago

A gas that effuses through a porous cylinder 1.87 times faster than chlorine gas. what is the molar mass and identity.

Rufina [12.5K]

From the Graham's law of effusion;
R1/R2 = √MM2/√MM1
Molar mass of chlorine gas is 71
Therefore;
1.87= √ 71 /√mm1
= 1.87² = 71/mm1
mm1 = 71/1.87²
= 71/3.4969
= 20.3
Thus, the molar mass of the other gas is 20.3 , and i think the gas is neon

6 0

3 years ago