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2 years ago

Which part of the Periodic Table of the elements is used to identify valence electrons? *

1 answer:

6 0

The number of valence electrons of an element can be determined by the periodic table group (vertical column) in which the element is categorized

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A stable atom that has a large nucleus most likely contains

maria [59]

Answer:

3. Equal numbers of protons and neutrons

Explanation:

The nucleus becomes unstable if the ratio of protons to neutrons is less than 1:1 or more than 1:1.5.

The most stable nucleus has a neutron proton ratio of 1:1 which means that they can not release a neutron or a proton to decay.

Nucleus 3 is therefore the most stable.

8 0

3 years ago

Indicate the type of observation that is best represented by the figures below.

Norma-Jean [14]

Qualitative because it changed its colour not its quantity :)

5 0

3 years ago

If a 95.27 mL sample of acetic acid (HC2H3O2) is titrated to the equivalence point with 79.06 mL of 0.113 M KOH, what is the pH

KATRIN_1 [288]

Answer:

8.73

Explanation:

The concentration of acetic acid can be determined as follows:

$M_1V_1 = M_2V_2\\(KOH) = (CH_3COOH)$

$M_{KOH}=0.113 M\\V_{KOH}=79.06 mL$

$V_{CH_3COOH}=95.27 \\\\M_{CH_3COOH)=?????$

$M_{CH3COOH} = \frac{M_{KOH}*V_{KOH}}{V_{CH_3COOH}}$

$M_{CH3COOH} = \frac{0.113*79.06}{95.27}$

$M_{CH3COOH} = 0.094 M$

Moles of $CH_3COOH$ = $95.27* 10^{-3}* 0.094$

=0.0090 moles

Moles of $KOH = 79.06*10^{-3}*0.113$

= 0.0090 moles

The equation for the reaction can be expressed as :

$CH_3COOH$ $+$ $KOH$ -----> $CH_3COO^{-}K^+$ $+$ $H_2O$

Concentration of $CH_3COO^{-$ ion = $\frac{0.0090}{Total volume (L)}$

= $\frac{0.0090}{(95.27+79.06)} *1000$

= 0.052 M

Hydrolysis of $CH_3COO^{-$ ion:

$CH_3COO^{-$ $+$ $H_2O$ -----> $CH_3COOH$ $+$ $OH^-$

$K = \frac{K_w}{K_a} = \frac{x*x}{0.052-x}$

⇒ $\frac{10^{-14}}{1.82*10^{-5}}= \frac{x*x}{0.052-x}$

= $0.5494*10^{-9}= \frac{x*x}{0.052-x}$

As K is so less, then x appears to be a very infinitesimal small number

0.052-x ≅ x

$0.5494*10^{-9}= \frac{x^2}{0.052}$

$x^2 = 0.5494*10^{-9}*0.052$

$x^2 = 0.286*10^{-10$

$x = \sqrt{0.286*10^{-10$

$x =0.535*10^{-5}M$

$[OH] = x =0.535*10^{-5}$

$pOH = -log[OH^-]$

$pOH = -log[0.535*10^{-5}]$

$pOH = 5.27$

pH = 14 - pOH

pH = 14 - 5.27

pH = 8.73

Hence, the pH of the titration mixture = 8.73

8 0

3 years ago

In your own words list the rules for naming hydrocarbons and substituted hydrocarbons. Be detailed in listing all rules includin

Irina18 [472]

Answer :

The basic rules for naming of hydrocarbons are :

First select the longest possible carbon chain.

The longest possible carbon chain should include the carbons of double or triple bonds.

The naming of alkane is done by adding the suffix -ane, alkene by adding the suffix -ene, alkyne by adding the suffix -yne.

The numbering is done in such a way that first carbon of double or triple bond gets the lowest number.

The carbon atoms of the double or triple bond get the preference over the other substituents present in the parent chain.

If two or more similar alkyl groups are present in a compound, the prefixes di-, tri-, tetra- and so on are used to specify the number of times of the alkyl groups in the chain.

8 0

3 years ago

If an element has 3 valance electrons what row is it in?

klemol [59]

It can be any row

Explanation:

An element with a valence electrons of 3 can be in any row on the periodic table.

The rows are the horizontal arrangement of elements on the periodic table.

Elements on the same row have the same energy level.

The periodic table rows are called periods.
It is only in the groups that we can find such element.
Group 3 elements have 3 valence electrons.
Since this group cuts through all the rows, therefore, elements with 3 valence electrons can be found in any row.

learn more:

Metalloids brainly.com/question/3023499

#learnwithBrainly

8 0

3 years ago