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3 years ago

How many dots would a dot diagram for selenium, one of the group 16 elements, have?

Chemistry

2 answers:

vodka [1.7K]3 years ago

4 0

Answer:

Because selenium is in the 16th column on the periodic chart, it has 6 valence electrons. Thus, the Lewis structure (or electron dot structure) for selenium has 6 dots around it.

It will look similar to this without the underscores:

__.

. Se:

_. .

Explanation:

Alex73 [517]3 years ago

4 0

Answer:

Explanation:

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The titration of 25.0 mL of an iron(II) solution required 18.0 mL of a 0.145 M solution of dichromate to reach the equivalence p

Svetlanka [38]

Answer:

0.64 M

Explanation:

Given:

Volume of iron(II) solution (V₁) = 25.0 mL = 0.025 L

Molarity of iron(II) solution (M₁) = ?

Number of moles of iron(II) solution (n₁) = ?

Volume of dichromate solution (V₂) = 18.0 mL = 0.018 L

Molarity of dichromate solution (M₂) = 0.145 M

Number of moles of dichromate solution (n₂) = ?

Molarity is equal to the ratio of moles and volume.

So, molarity of dichromate solution is given as:

$M_2=\frac{n_2}{V_2}\\\\n_2=M_2\times V_2=0.145\times 0.018 = 2.61\times 10^{-3}\ mol$

Now, let us write the complete balanced reaction for the given situation.

So, the complete balanced equation is given below.

$6Fe^{2+}(aq)+Cr_2O_7^{2-}(aq)+14H^+(aq)\to 6Fe^{3+}(aq)+2Cr^{3+}(aq)+7H_2O$

From the equation, it is clear that, 1 mole of dichromate is required for 6 moles of iron(II) solution.

So, using unitary method, we find the number of moles of iron(II) solution.

1 mole of dichromate = 6 moles of iron(II)

∴ n₂ moles of dichromate = 6n₂ moles of iron(II)

= $6\times 2.61\times 10^{-3}=0.016\ mol\ Fe^{2+}$

So, 0.016 moles of iron(II) is needed. Therefore, $n_1=0.016\ mol$

Now, molarity of iron(II) solution is given as:

Molarity = Moles ÷ Volume

$M_1=\frac{n_1}{V_1}\\\\M_1=\frac{0.016\ mol}{0.025\ L}=0.64\ M$

Therefore, the molarity of the iron(II) solution is 0.64 M.

4 0

3 years ago

What characterizes a homogeneous mixture?

Vadim26 [7]

It has the same composition throughout, unlike a heterogeneous which has visibly separate substances

4 0

3 years ago

What is the overall charge of the compound frbr

sammy [17]

Answer:

Zero

Explanation:

FrBr is an ionic compound .

Fr is in Group 1. Br is in Group 17.

The charges on the ions are +1 and -1, respectively.

The compound consists of Fr⁺Br⁻ ions.

However, there are equal numbers of + and - charges, so

The overall charge of the compound is zero.

5 0

3 years ago

(a) if a sample containing 2.00 ml of nitroglycerin is detonated, how many total moles of gas are produced? (b) if each mole of

gregori [183]

Detonation of nitroglycerin:

$4C_3H_5N_3O_9 ------\ \textgreater \ 12CO_2+6N_2+O_2+H_2O$

Mass nitroglycerin = 2.00 mL x 1.592 g/mL = 3.184 g

Moles = mass / molar mass = 3.184 g/ 227.0872 g/mol = 0.01402

the ratio between nitroglycerin and Carbon dioxide is 4 : 12
So, moles CO2 = 0.01402 x 12 / 4 =0.0420

the ratio between nitroglycerin and N2 is 4 : 6
moles N2 = 0.01402 x 6 / 4 =0.0841

the ratio between nitroglycerin and O2 is 4 : 1 
moles O2 = 0.01402 x 1 / 4 = 0.0035

the ratio between nitroglycerin and water is 4 : 1 
in the same way moles water = 0.005258 

total moles = 0.0420 + 0.0841 + 0.0035 + 0.005258 = 0.130758

0.130758 x 55 = 5.78 L 

Mass N2 = 0.0841 mol x 28.0134 g/mol = 2.3548 g

6 0

3 years ago

1. Baking soda and vinegar combined *

Alina [70]

Answer:

dont know

Explanation:

4 0

3 years ago