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2 years ago

Fossils are the preserved remains or traces of an organism that used to be alive.

Chemistry

2 answers:

kotykmax [81]2 years ago

8 0

Answer:

This is True

Explanation:

A fossil is any remains or trace of an ancient organism. Fossils include body fossils, left behind when the soft parts have decayed away, as well as trace fossils

Evgesh-ka [11]2 years ago

3 0

True because the definition of a fossil is “the remains or impression of a prehistoric organism preserved in petrified form or as a mold or cast in rock.”

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A series of lines involving a common level in the spectrum of atomic hydrogen lies at 656.46 nm, 486.27 nm, 434.17 nm, and 410.2

alexandr402 [8]

Answer:

1) the wavelength of the next line in the series is 397.2 nm

2) The ionization energy is 3.3996 eV

Explanation:

Step 1: Data given

A series of lines involving a common level in the spectrum of atomic hydrogen lies at 656.46 nm, 486.27 nm, 434.17 nm, and 410.29 nm

Step 2: Calculate n₂

The visible spectrum of light from hydrogen displays four wavelengths, 410 nm, 434 nm, 486 nm, and 656 nm,

1/λ = Rh *(1/n₁² - 1/n₂² )

⇒with λ = the wavelength

⇒with Rh = Rydberg constant for hydrogen, 1.09677583 * 10^7 m

⇒ with n₁ = the principal quantum number of an energy level

⇒with n₂ = the principal quantum number of an energy level for the atomic electron transition

λ * Rh = n₁²* (n₁+1)² / (2n₁² + 1)

656.46 nm * 109677 cm = n₁²* (n₁+1)² / (2n₁² + 1)

7.20 = n₁²* (n₁+1)² / (2n₁² + 1)

n1 = 2

All those are in the visible spectrum and are called Balmer series, or Balmer lines.

n1 (the principal quantum number of an energy level) for Balmer series is: n1 = 2

Step 3: calculate he wavelength of the next line in the series?

1/λ = Rh *(1/n₁² - 1/n₂² )

⇒with n₂ = the principal quantum number of an energy level for the atomic electron transition = 7

1/λ = 109677.6 / cm * (1/2² - 1/7²)

1/λ = 109677.6 / cm * (1/4 - 1/51.84)

λ = 397.2 nm

the wavelength of the next line in the series is 397.2 nm

Step 4: What is the ionization energy of the atom when it is in the lower state of the transitions?

The energy required to ionize the atom is:

n₂ → ∞

V∞ = 1/λ = 109677.6 / cm * (1/4 - 0)

V∞ = 109677.6 * 1 eV/ 8065.5 cm-1

V∞ = 27419.25 * 1 eV / 8065.5 cm-1

V∞ = 3.3996 eV

The ionization energy is 3.3996 eV

8 0

3 years ago

Can someone pleas help

bekas [8.4K]

Answer:

Looks like a balloon to me

Explanation:

3 0

3 years ago

In a longitudinal wave moving along a spring, what are areas where the coils are farthest apart called?

Sholpan [36]

Areas of rarefaction

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3 years ago

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According to the cooling curve, what is the approximate freezing point of the substance?

Dmitry_Shevchenko [17]

Correct answer: B

Cooling curve is the plot of temperature versus time as the sample is allowed to cool. In a cooling curve, we start at a temperature greater than the boiling point. At this temperature, the sample is in gaseous state. At the boiling point, there is no change in temperature as the gaseous and liquid states are in equilibrium. As the temperature reduces further, the liquid starts to condense and at the melting point of the sample the liquid undergoes phase transition to solid state. At the melting temperature, a second plateau is observed as the temperature remains unchanged. At temperatures below the melting point, the sample exists as a solid.

So from the curve, the second plateau is observed at around -111 $^{0}C$ . This point represents the phase transition from liquid to solid state.

6 0

3 years ago

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What do elements in a same group share

Setler79 [48]

Answer:

The elements in each group have the same number of electrons in the outer orbital. Those outer electrons are also called valence electrons. They are the electrons involved in chemical bonds with other elements. Every element in the first column (group one) has one electron in its outer shell.

Explanation:

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2 years ago

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