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3 years ago

How many protons does the bohr model have for helium?

Chemistry

1 answer:

Brilliant_brown [7]3 years ago

8 0

Answer:

2 protons per atom of Helium

Explanation:

The number of proton in a given element is given by its place on the periodic table which is for He 2 protons b/c the atomic number for He is 2.

Other Examples:

Hydrogen (H-1) or Protium has 1 proton b/c its atomic number is 1.

Magnesium (Mg-24) has 24 protons b/c its atomic number is 24.

Lead (Pb-207) has 82 protons b/c its atomic number is 82.

Uranium (U-238) has 92 protons b/c its atomic number is 92.

The periodic table order of arrangement of elements is based upon 'The Periodic Law'. => The chemical and physical properties of the elements is a periodic function of atomic numbers, or number of protons in the nucleus.

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Why can't the subscripts be changed?

zlopas [31]

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A student prepares a aqueous solution of trimethylacetic acid . Calculate the fraction of trimethylacetic acid that is in the di

irinina [24]

The question is incomplete, here is the complete question:

A student prepares a 0.21 mM aqueous solution of trimethylacetic acid. Calculate the fraction of trimethylacetic acid that is in the dissociated form in his solution. Express your answer as a percentage. You will probably find some useful data in the ALEKS Data resource. Round your answer to 3 significant digits.

Answer: The percent of dissociation of trimethylacetic acid is 19.5 %

Explanation:

We are given:

Concentration of trimethylacetic acid = 0.21 mM = 0.00021 M (Conversion factor: 1 mole = 1000 millimoles )

The chemical equation for the dissociation of trimethylacetic acid follows:

$C_4H_9COOH\rightleftharpoons C_4H_9COO^-+H^+$

Initial: 0.00021

At eqllm: 0.00021-x x x

The expression of $K_a$ for above equation follows:

$K_a=\frac{[C_4H_9COO^-][H^+]}{[C_4H_9COOH]}$

We know that:

$K_a\text{ for }C_4H_9COOH=1\times 10^{-5}$

Putting values in above expression, we get:

$1\times 10^{-5}=\frac{x\times x}{(0.00021-x))}\\\\x=0.000041,-0.000051$

Neglecting the negative value of 'x' because concentration cannot be negative.

To calculate the fraction of dissociation, we use the equation:

$\text{Percent of dissociation}=\frac{[H^+]}{[C_4H_9COOH]}\times 100$

Putting values in above equation, we get:

$\text{Percent of dissociation}=\frac{0.000041}{0.00021}\times 100\\\\\text{Percent of dissociation of trimethylacetic acid}=19.5%$

Hence, the percent of dissociation of trimethylacetic acid is 19.5 %

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3 years ago

What happens during ice wedging

jek_recluse [69]

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4 years ago

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