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4 years ago

Red light with a wavelength of 670.8 nm is emitted when lithium is heated in a flame

Chemistry

1 answer:

Sav [38]4 years ago

3 0

Answer:

Frequency = 4.5 × 10¹⁴ Hz

Explanation:

Given data:

Wavelength of light = 670.8 nm (670.8 ×10⁻⁹ m)

Frequency of light = ?

Solution:

Speed of light = wavelength × frequency

Frequency = Speed of light / wavelength

Speed of light = 3 × 10⁸ m/s

Frequency = 3 × 10⁸ m/s / 670.8 ×10⁻⁹ m

Frequency = 0.0045 × 10¹⁷ s⁻¹

Frequency = 4.5 × 10¹⁴s⁻¹

s⁻¹ = Hz

Frequency = 4.5 × 10¹⁴ Hz

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Why does Ethanol have a higher vapor pressure than Pentanol?

Zarrin [17]

Answer:

Water is much smaller than either of the previous substances and exhibits weaker dispersion forces, but its extensive hydrogen bonding provides stronger intermolecular attractions, fewer molecules escaping the liquid, and lower vapor pressure than for either diethyl ether or ethanol.

Explanation:

Brain-List

7 0

3 years ago

How much energy is required to melt these quantities of ice? a. 56 g b. 56 mol

Dmitrij [34]

The enthalpy is the amount of energy required to change from solid to liquid.

The molar enthalpy of fusion (kJ/mol) is 6.01 kJ/mol.

We can answer B first, since solving for A would require us to find moles, which takes more time.

q = H*n
q = 6.01*56
q = 336.56 kJ

On to a.

Since we know the molar enthalpy of fusion, we need to solve for the number of moles in 56 grams of ice.

n = 56/(16.00 + 2(1.008))
n = 3.108 mol

Now we can solve.

q = H * n
q = 6.01 * 3.108
q = 18.7 kJ

Answers:
a. 18.7 kJ
b. 336.56 kJ

Let me know if you'd like me to explain anything I did here.

-T.B.

4 0

4 years ago

A solution containing 4.15 g of magnesium chloride is added to a second solution containing excess

AveGali [126]

Answer:

1. 5.24 g

2. 75.4%

Explanation:

We'll begin by writing the balanced equation for the reaction. This is illustrated below:

MgCl₂ + Na₂SO₄ —> MgSO₄ + 2NaCl

Next, we shall determine the mass of MgCl₂ that reacted and the mass of MgSO₄ produced from the balanced equation. This can be obtained as follow:

Molar mass of MgCl₂ = 24 + (35.5×2)

= 24 + 71

= 95 g/mol

Mass of MgCl₂ from the balanced equation = 1 × 95 = 95 g

Molar mass of MgSO₄ = 24 + 32 + (16×4)

= 24 +32 + 64

= 120 g/mol

Mass of MgSO₄ from the balanced equation = 1 × 120 = 120 g

SUMMARY:

From the balanced equation above,

95 g of MgCl₂ reacted to produce 120 g of MgSO₄.

1. Determination of the ideal yield of magnesium sulfate, MgSO₄.

From the balanced equation above,

95 g of MgCl₂ reacted to produce 120 g of MgSO₄.

Therefore, 4.15 g of MgCl₂ will react to produce = (415 × 120)/95 = 5.24 g of MgSO₄.

Thus, the ideal yield of magnesium sulfate, MgSO₄ is 5.24 g

2. Determination of the percentage yield.

Actual yield of MgSO₄ = 3.95 g

Ideal yield of MgSO₄ = 5.24 g

Percentage yield =?

Percentage yield = Actual yield / Ideal yield × 100

Percentage yield = 3.95 / 5.24 × 100

Percentage yield = 395 / 5.24

Percentage yield of MgSO₄ = 75.4%

7 0

3 years ago

Need help asap!!!!! Plz

Nostrana [21]

Answer:

153.8 g/mol.

Explanation:

The molar mass of a compound = ∑ atomic masses of atoms.

∴ The molar mass of CCl₄ = 1(atomic masss of C) + 4 (atomic mass of Cl) = (12.0 g/mol) + 4 (35.45 g/mol) = 153.8 g/mol.

6 0

3 years ago

During cellular respiration, chemical energy is converted to cellular energy. (2 points) True False

Alchen [17]

During cellular respiration, chemical energy is converted to cellular energy. (2 points) True False

It is a process of oxidation of glucose to produce large amount of energy along with carbon dioxide and water

4 0

4 years ago