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3 years ago

how does a spectral signature help scientists determine the composition of planets and other stars???

Chemistry

1 answer:

sveticcg [70]3 years ago

6 0

Answer:

How do scientists determine the chemical compositions of the planets and stars? Each element absorbs light at specific wavelengths unique to that atom. When astronomers look at an object's spectrum, they can determine its composition based on these wavelengths. ... That fingerprint often appears as the absorption of light.

Explanation:

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A. Gallium is produced by the electrolysis of a solution obtained by dissolving gallium oxide in concentrated NaOH(aq). Calculat

liraira [26]

Answer:

A)Mass of gallium plated out is 0.3440 grams

B) For 0.67 hours current of 5.79 A must to be applied to plate out 8.70 g of tin.

Explanation:

To calculate the total charge, we use the equation:

$C=I\times t$

where,

C = Charge

I = Current in time t (seconds)

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

$\text{Moles of electrons}=\frac{C}{F}$

where,

F = Faraday's constant = 96500

A) The equation for the deposition of Ga(s) from Ga(III) solution follows:

$Ga^{3+}(aq.)+3e^-\rightarrow Ga(s)$

I = 0.790 A, t = 30.0 min = 1800 seconds

$C=I\times t$

$C=0.790 A\times 1800 s=1422 C$

Moles of electron transferred:

$=\frac{1422 C}{96500 F}=0.01474 mol$

Now, to calculate the moles of gallium, we use the equation:

$\text{Moles of Gallium}=\frac{\text{Moles of electrons}}{n}$

n = number of electrons transferred = 3

$\text{Moles of Gallium}=\frac{0.01474 mol}{3}=0.004913 mol$

Mass of 0.004913 moles of gallium = 0.004913 mol × 70 g/mol=0.3440 g

B) The equation for the deposition of Sn(s) from Sn(II) solution follows:

$Sn^{2+}(aq.)+2e^-\rightarrow Sn(s)$

Moles of tin = $\frac{8.70 g}{119 g/mol}=0.07311 mol$

n = number of electrons transferred = 2

$\text{Moles of tin}=\frac{\text{Moles of electrons}}{n}$

Moles of electron = $n\times \text{Moles of tin}$

$=2\times 0.07311 mol=0.14622 mol$

Charge transferred during time t :

$\text{Moles of electrons}=\frac{C}{F}$

$C=96500 F\times 0.14622 mol=14,110.23 C$

Current applied for t time = I = 5.79 A

$t=\frac{C}{I}=\frac{14,110.23 C}{5.79 A}=2,437 s=0.67 hrs$

For 0.67 hours current of 5.79 A must to be applied to plate out 8.70 g of tin.

5 0

3 years ago

Which of the following would be a value measured using a scale in lab?

Neko [114]

Answer:

A. Actual Yield

Since all of the others are calculated not measured outright.

4 0

3 years ago

In a calorimeter, a 1.0 g sample of magnesium is burned to form mgo. in doing so, 25.5 kj of energy are released. what is the mo

Artemon [7]

The molar enthalpy of combustion in kj/mol of magnesium is 620 kj/mol, Option D is the correct answer.

<h3>What is enthalpy of Combustion ?</h3>

The energy released when a fuel is oxidized by an oxidizing agent is called enthalpy of Combustion.

It is given that

a 1.0 g sample of magnesium is burned to form MgO. in doing so, 25.5 kj of energy are released.

Molecular weight of Magnesium = 24.35g

24.35 g makes 1 mole of Mg

1g = 1/24.35

For 0.04 moles 25.5 kJ is released

for 1 mole 25.5 *1/.04

= 620 kj/mol

Therefore the molar enthalpy of combustion in kj/mol of magnesium is 620 kj/mol.

To know more about enthalpy of combustion

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3 0

2 years ago

How many molecules are in 165 g of carbon dioxide?

Svet_ta [14]

М(СО₂)=165 г

н(СО₂)=м(углекислого газа)/М(СО₂)

Н=Nₐ*м(углекислого газа)/М(СО₂)

Н=6.022*1023 * 165/44.01=2.258*10²⁴

6 0

3 years ago

Read 2 more answers

How many moles of nitrogen N are in 71.0g of nitrous oxide , N2O

timama [110]

1.6 moles of N2 in 71g

8 0

3 years ago

Read 2 more answers