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2 years ago

HELP PLEASE I dont understand this (7th Grade science)

Chemistry

2 answers:

Aleonysh [2.5K]2 years ago

8 0

The first is chemical

Maksim231197 [3]2 years ago

7 0

For the second one it is physical

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2) Which of the following statements best describes an element?

mixas84 [53]

Answer:

Explanation:

The answer woul be E because elements are made of one type of atoms

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3 years ago

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Does a periodic table indicate the occurrence of elements

guajiro [1.7K]

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Explanation:

it only shows the atomic number and basically the chemical behavior of the element

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2 years ago

Rocks are classified according to their composition and color. true or false

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True :)

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When an electron in a 2p orbital of a particular atom makes a transition to the 2s orbital, a photon of approximate wavelength 6

Mariulka [41]

Answer:

The energy difference between these 2p and 2s orbitals is $3.07\times 10^{-19} J$

Explanation:

Wavelength of the photon emitted = $\lambda =646.3 nm =646.3\times 10^{-9} m$

Energy of the photon will corresponds to the energy difference between 2p and 2s orbital = E

Energy of the photon is given by Planck's equation:

$E=\frac{hc}{\lambda }$

h = Planck's constant = $6.626\tiomes 10^{-34} Js$

c = Speed of the light = $3\times 10^8 m/s$

$E=\frac{6.626\tiomes 10^{-34} Js\times 3\times 10^8 m/s}{646.3\times 10^{-9} m}$

$E=3.07\times 10^{-19} J$

The energy difference between these 2p and 2s orbitals is $3.07\times 10^{-19} J$

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3 years ago

What are the compounds empirical and molecular formulas

Liono4ka [1.6K]

Answer:

The empirical formula is the simplest ratio of atoms while molecular is the actual formula.

Explanation:

Empirical Formula is the simplest ratio of atoms present in the compound.

The molecular formula shows the actual number of atoms present in the compound.

For example, CH is the empirical formula and C6H6 is the molecular formula of benzene.

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1 year ago