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4 years ago

8

A scientist studies an element that has seven electrons in its outer shell, is fairly toxic, and is highly reactive. To which gr

oup of the periodic table does this element belong

1 answer:

tangare [24]4 years ago

3 0

Answer:17

Explanation:cause i took the test

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How many grams of propanol (C3H7OH, 60.10 g/mol) would be needed to make 750 mL of a solution with an osmotic pressure of 25 atm

Ierofanga [76]

Answer:

= 46.06 grams

Explanation:

P=cRT

25 = c (0.0821)(298)

concentration = c = 1.021 M

number of moles = (1.021)(0.75) = 0.7664 moles

mass = (0.7664)(60.10)=40.06 grams

3 0

3 years ago

What are the 4 elements of amazonite

steposvetlana [31]

Aluminum, silicon, potassium and oxygen.

6 0

3 years ago

Be sure to answer all parts. for each reaction, find the value of δso. report the value with the appropriate sign. (a) 3 no2(g)

Maurinko [17]

Answer:

Change in entropy for the reaction is

ΔS° = -268.13 J/K.mol

Explanation:

To calculate the change in entropy for the balanced reaction, we require the natural entropy of all the reactants and products in the reaction.

3 NO₂(g) + H₂O(l) → 2 HNO₃(l) + NO(g)

From Literature.

S°(NO₂) = 240.06 J/K.mol

S°(H₂O) = 69.91 J/K.mol

S°(HNO₃) = 155.60 J/K.mol

S°(NO) = 210.76 J/K.mol

These are the entropies of the reactants and products under standard conditions of 298.15 K and 1 atm.

Note that

ΔS° = Σ nᵢS°(for products) - Σ nᵢS°(for reactants)

Σ nᵢS°(for products) = [2 × S°(HNO₃)] + [1 × S°(NO)]

= (2 × 155.60) + (1 × 210.76) = 521.96 J/K.mol

Σ nᵢS°(for reactants) = [3 × S°(NO₂)] + [1 × S°(H₂O)]

= (3 × 240.06) + (1 × 69.91) =790.09 J/K.mol

ΔS° = Σ nᵢS°(for products) - Σ nᵢS°(for reactants)

ΔS° = 521.96 - 790.09 = -268.13 J/K.mol

Hope this Helps!!

4 0

4 years ago

Write the empirical formula of at least four binary ionic compounds that could be formed from the following ions:

Mazyrski [523]

Ionic compounds are the compounds consists of positive and negative ions.
<span>Zn(2+):------
</span><span>ZnBr2:
ZnS:
</span>Al(+3):------
Al203
Al2(SO4)^3
<span>Cl:(1-)
NaCl </span>

7 0

4 years ago

The strength of a covalent bond depends upon the size of the atoms and the bond order. In general short bonds are strong bonds.1

Oksana_A [137]

Answer:

<u>Bond energy of</u> (A) C≡C > (B) C=C

<u>and, </u>(C) C=N > (D) C-N

Explanation:

Bond energy refers to the amount of energy required to break a bond or the energy released when a bond is formed. Bond energy of a covalent bond suggests the bond strength of the chemical bond and depends on the <u>bond length and bond order of the chemical bond. </u>

<u>The bond energy of a chemical bond increases with the bond order and decreases with the bond length</u>. As, length of a bond decreases with increase in the bond order.

First pair: (A) C≡C (B) C=C

The bond order of C≡C - 3, the bond order of C=C - 2

Since the bond order: C≡C > C=C

Bond length: C≡C < C=C

<u>Therefore, bond energy of (A) C≡C > (B) C=C</u>

Second pair: (C) C=N (D) C-N

The bond order of C=N - 2, the bond order of C-N - 1

Since the bond order: C=N > C-N

Bond length: C=N < C-N

<u>Therefore, bond energy of (C) C=N > (D) C-N</u>

8 0

4 years ago