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Makovka662 [10]

3 years ago

9

What is the longest wavelength in the Balmer series? (Hint: the Rydberg constant for Hydrogen is 1.096776×107 1/m, and the Balme

r series is the second series of lines in the spectrum of the Hydrogen.)

1 answer:

boyakko [2]3 years ago

4 0

<u>Answer:</u> The longest wavelength of light is 656.5 nm

<u>Explanation:</u>

For the longest wavelength, the transition should be from n to n+1, where: n = lower energy level

To calculate the wavelength of light, we use Rydberg's Equation:

$\frac{1}{\lambda}=R_H\left(\frac{1}{n_i^2}-\frac{1}{n_f^2} \right )$

Where,

$\lambda$ = Wavelength of radiation

$R_H$ = Rydberg's Constant = $1.096776\times 10^7m^{-1}$

$n_f$ = Higher energy level = $n_i+1=(2+1)=3$

$n_i$ = Lower energy level = 2 (Balmer series)

Putting the values in above equation, we get:

$\frac{1}{\lambda }=1.096776\times 10^7m^{-1}\left(\frac{1}{2^2}-\frac{1}{3^2} \right )\\\\\lambda =\frac{1}{1.5233\times 10^6m^{-1}}=6.565\times 10^{-7}m$

Converting this into nanometers, we use the conversion factor:

$1m=10^9nm$

So, $6.565\times 10^{-7}m\times (\frac{10^9nm}{1m})=656.5nm$

Hence, the longest wavelength of light is 656.5 nm

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1 mole of CH4 results to 2 moles of H2O.

If 8.5 liters are to be produced, then (1CH4/2H20)*(8.5L h2o) = 4.25L CH4

6 0

4 years ago

When you see or visit grasslands, what do you know about the climate? (Select all that apply.)

Nana76 [90]

When you see or visit grasslands you know that :

They have mild to hot summers ( B )
They have a lot of precipitation ( A )

<h3><u>Grassland vegetation</u> </h3>

Grasslands are a type of vegetation found mostly in areas with favourable weather conditions such as mild summers and right amount of precipitation which provides the grasslands with enough water for proper growth.

Other types of vegetation include :

Forest vegetation
Tundra and
Desert vegetation

Desert vegetation expreciences very hot summers and little precipitation which leads to the scarcity of green vegetation, while forest vegetation expreciences a very high level of precipitation.

Hence we can conclude that When you see or visit grasslands you know that :They have mild to hot summers ,They have a lot of precipitation

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4 0

3 years ago

Read 2 more answers

1. 51.2 g of NaClO (pKa of HClO is 7.50) and 25.3 g of KF (pKa of of HF is 3.17) were combined in enough water to make 0.250 L o

Andrews [41]

Answer:

* $pH=11.0$

* $[HClO]_{eq}=9.32x10^{-4}M$

* $[HF]_{eq}=5.07x10^{-6}M$

Explanation:

Hello,

At first, the molarities of NaClO and KF are computed as shown below:

$M_{NaClO}=\frac{51.2g*\frac{1mol}{74.45g} }{0.250L}=2.75M \\\\M_{KF}=\frac{25.3g*\frac{1mol}{58.1g} }{0.250L} =1.74M$

Now, since both NaClO and KF are ionic, one proposes the dissociation reactions as:

$NaClO\rightarrow Na^++ClO^-\\KF\rightarrow K^++F^-$

In such a way, by writing the formation of HClO and HF respectively, due to the action of water, we obtain:

$ClO^-+H_2O\rightleftharpoons HClO+OH^-\\F^-+H_2O\rightleftharpoons HF+OH^-\\$

Now, the presence of OH⁻ immediately implies that Kb for both NaClO and KF must be known as follows:

$Kb=\frac{Kw}{Ka} \\Kb_{NaClO}=\frac{1x10^{-14}}{10^{-7.50}}=3.16x10^{-7}\\Kb_{KF}=\frac{1x10^{-14}}{10^{-3.17}}=1.48x10^{-11}$

In such a way, the law of mass action for each case is:

$Kb_{NaClO}=3.16x10^{-7}=\frac{[HClO][OH]^-}{[ClO^-]}=\frac{(x_{ClO})(x_{ClO})}{2.75-x_{ClO}}\\Kb_{KF}=1.48x10^{-11}=\frac{[HF][OH]^-}{[F^-]}=\frac{(x_{F})(x_{F})}{1.74-x_{F}}$

Now, by solving for the change $x$ for both the ClO⁻ and F⁻ equilibriums, we obtain:

$x_{ClO}=9.32x10^{-4}M\\x_{F}=5.07x10^{-6}M$

Such results equal the concentrations of OH⁻ in each equilibrium, thus, the total concentration of OH⁻ result:

$[OH^-]_{tot}=9.32x10^{-4}M+5.07x10^{-6}M=9.37x10^{-4}M$

With which the pOH is:

$pOH=-log(9.37x10^{-4})=3.03$

And the pH:

$pH=14-pOH=11.0$

In addition, the equilibrium concentrations of HClO and HF equals the change $x$ for each equilibrium as:

$[HClO]_{eq}=x_{ClO}=9.32x10^{-4}M$

$[HF]_{eq}=x_{F}=5.07x10^{-6}M$

Best regards.

6 0

3 years ago

When two nitrogen atoms bond together, they form the diatomic molecule N2. Which

kirill [66]

convalent

Explanation:

I hope its helps u

8 0

3 years ago

Read 2 more answers

Three glass bulbs, joined by closed stopcocks, have the following volumes and initial pressures of the specified gases. Bulb A:

Molodets [167]

Answer:

1. Total pressure is 475 torr.

2. The partial pressure of CO is 23.8 torr.

3. The mole fraction of CO is 0.0501.

Explanation:

We have 3 gases in different bulbs. Once the stopcocks are opened, they share the same final volume which is the sum of all individual volumes.

V = Va + Vb + Vc = 150 mL + 300 mL + 750 mL = 1200 mL

Since we know initial pressures and volumes for each gas, we can find the final pressures using Boyle's Law. The mathematical expression is

P₁ . V₁ = P₂ . V₂

We assume that temperature remains constant and that gases behave as ideal gases.

CO

P₁ = 190 torr; V₁ = 150 mL; P₂ = ?; V₂ = 1200 mL

P₁ . V₁ = P₂ . V₂

190 torr . 150 mL = P₂ . 1200 mL

P₂ = 23.8 torr

Ar

P₁ = 0.500 atm; V₁ = 300 mL; P₂ = ?; V₂ = 1200 mL

P₁ . V₁ = P₂ . V₂

0.500 atm . 300 mL = P₂ . 1200 mL

P₂ = 0.125 atm

$P_{2}=0.125atm.\frac{760torr}{1atm} =95.0torr$

Kr

P₁ = 75.994 kPa ; V₁ = 750 mL; P₂ = ?; V₂ = 1200 mL

P₁ . V₁ = P₂ . V₂

75.994 kPa . 750 mL = P₂ . 1200 mL

P₂ = 47.5 kPa

$P_{2}=47.5kPa.\frac{7.50torr}{1kPa} =356torr$

The total pressure is the sum of partial pressures.

P = P(CO) + P(Ar) + P(Kr) = 23.8 torr + 95.0 torr + 356 torr = 475 torr

We can find the mole fraction of of CO using the following expression, based on Dalton's Law:

P(CO) = P . X(CO)

where,

X(CO) is the mole fraction of CO

Then,

X(CO) = P(CO)/P = 23.8 torr / 475 torr = 0.0501.

5 0

3 years ago