Answer:
Dalton's atomic theory consisted of several postulates.
Explanation:
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All matter consists of indivisible particles called atoms.
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Atoms of the same element are similar in shape and mass, but differ from the atoms of other elements.
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Atoms cannot be created or destroyed.
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Atoms of different elements may combine with each other in a fixed, simple, whole number ratio to form compound atoms.
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Atoms of same element can combine in more than one ratio to form two or more compounds.
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Atoms are the smallest unit of matter that can take part in a chemical reaction.
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Answer:
C. 0.4.
Explanation:
<em>∵ mole fraction of acetic acid (X acetic acid) = (no. of moles acetic acid)/(total no. of moles) = (no. of moles acetic acid)/(no. of moles of acetic acid + no. of moles of water).</em>
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- no. of moles of acetic acid = 2, no. of moles of water = 3.
- Total no. of moles = no. of moles of acetic acid + no. of moles of water = 2 + 3 = 5.
<em>∴ mole fraction of acetic acid (X acetic acid) = (no. of moles acetic acid)/(total no. of moles) =</em> (2)/(5)<em> = 0.4.</em>
Answer:
1.64x10⁻¹⁸ J
Explanation:
By the Bohr model, the electrons surround the nucleus of the atom in shells or levels of energy. Each one has it's energy, and the electron doesn't fall to the nucleus because it can reach another level of energy, and then return to its level.
When the electrons go to another level, it absorbs energy, and then, when return, this energy is released, as a photon (generally as luminous energy). The value of the energy can be calculated by:
E = hc/λ
Where h is the Planck constant (6.626x10⁻³⁴ J.s), c is the light speed (3.00x10⁸ m/s), and λ is the wavelength of the photon.
The wavelength can be calculated by:
1/λ = R*(1/nf² - 1/ni²)
Where R is the Rydberg constant (1.097x10⁷ m⁻¹), nf is the final orbit, and ni the initial orbit. So:
1/λ = 1.097x10⁷ *(1/1² - 1/2²)
1/λ = 8.227x10⁶
λ = 1.215x10⁻⁷ m
So, the energy is:
E = (6.626x10⁻³⁴ * 3.00x10⁸)/(1.215x10⁻⁷)
E = 1.64x10⁻¹⁸ J
Answer:
-209 kJ
Explanation:
I did the math. You're welcome ;)
Answer:
The formula for calculating pH is pH=−log[H_3O+ ]
pH is the negative logarithm (to base 10) of hydronium ion concentration
The pH Formula can also be expressed as
PH= - log[H+ ]
