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3 years ago

How can you find the amount of valence electrons an atom of an element contains?

Chemistry

1 answer:

seraphim [82]3 years ago

3 0

Answer:

For neutral atoms, the number of valence electrons is equal to the atom's main group number. The main group number for an element can be found from its column on the periodic table. For example, carbon is in group 4 and has 4 valence electrons. Oxygen is in group 6 and has 6 valence electrons.

Explanation:

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How does a catalyst affect the activation energy of a chemical reaction?

FromTheMoon [43]

It lowers the activation energy.

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3 years ago

Doppler shifted hydrogen absorption lines are seen in the spectrum of a star. The hydrogen line at 656.28 nm is seen to be shift

snow_lady [41]

Answer:

The Star is moving towards us

Explanation:

Since there is a reduction in shift from the hydrogen line.

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2 years ago

A student determines the aluminum content of a solution by first precipitating it as aluminum hydroxide, and then decomposing th

Vladimir [108]

Answer: The student should obtain 1.103 g of aluminum oxide 

Explanation:

First we write down the equations that represent the aluminum hydroxide precipitation from the reaction between the aluminum nitrate and the sodium hydroxide:

Al(NO3)3 + 3NaOH → 3NaNO3 + Al(OH)3

Now, the equation that represents the decomposition of the hydroxide to aluminum oxide by heating it.

2Al(OH)3 → Al2O3 + 3H2O

Second, we gather the information what we are going to use in our calculations.

Volumen of Al(NO3)3 = 40mL

Molar concentration of Al(NO3)3 = 0.541M

Molecular Weight Al2O3 = 101.96 g/mol

Third, we start using the molar concentration of the aluminum nitrate and volume used to find out the total amount of moles that are reacting

$\frac{0.541moles Al(NO3)3}{1L} x\frac{1L}{1000mL} x 40mL Al(NO3)3 = 0.022moles Al(NO3)3$

then we use the molar coefficients from the equations to discover the amount of Al2O3 moles produced

$0.022moles Al(NO3)3 x \frac{1mol Al(OH)3}{1mol Al(NO3)3} X\frac{1mol Al2O3}{2molAl(OH)3} = 0.011 moles Al2O3$

finally, we use the molecular weight of the Al2O3 to calculate the final mass produced.

$0.011moles Al2O3 x \frac{101.96g Al2O3}{1mol Al2O3} = 1.103g Al2O3$

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3 years ago

2,2-dimethyl-4-propyloctane has how many secondary carbons? view available hint(s) 2,2-dimethyl-4-propyloctane has how many seco

Citrus2011 [14]

Structure of 2,2-dimethyl-4-propyloctane is in the Word document below.
Answer is: six secondary carbons.
Secondary carbon (2°) is attached to two other carbons. Secundary carbons are third, fifth, sixth and seventh in octane and first and second in propyl.
Primary carbon (1°) is attached to only one carbon.
Tertiary carbon (3°) is attached to three other carbons.
Quaternary carbon (4°) is attached to four other carbons.

Download docx

7 0

2 years ago

I need help fast please !

Alona [7]

Answer:

substance A is water and substance B is chlorophyll

Explanation:

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3 years ago

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