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Elena L [17]
3 years ago
11

A) Compute the repeat unit molecular weight of polystyrene. B) Compute the number-average molecular weight for a polystyrene for

which the degree of polymerization is 25,000.
Chemistry
1 answer:
Andrej [43]3 years ago
7 0

Answer:

Explanation:

In Polystrene, the molecular formula for the repeat unit = C_8H_8;

and the atomic weights of Carbon C = 12.01 g/mol

For Hydrogen, it is 1.01 g/mol

Hence, the repeat unit molecular weight is:

m = 8 (12.01 g/mol)+8(1.01 g/mol)

m = 96.08 g/mol + 8.08 g/mol

m = 104.16 g/mol

The degree of polymerization = no-average molecular weight/repeat unit molecular weight.

Mathematically;

DP = \dfrac{\overline M_n}{m}

\overline M_n= DP \times m

\overline M_n= 25000 \times 104.16 \ g/mol

\overline M_n= 2604000  \ g/mol

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Which group or groups of atoms are the only atoms with f orbitals A. All atoms heavier than barium B. All atoms heavier than kry
Mashcka [7]

Answer:

All atoms heavier than barium

Explanation:

In the periodic table, elements are divided into blocks. We have the;

s- block elements

p- block elements

d- block elements

f- block elements

However, immediately after Barium, we now encounter elements that have f-orbitals. Barium possesses a fully filled d-orbital. Hence after it, we see elements with 4f and 5f orbitals called the Lanthanides and actinides. The elements following the lanthanide and actinide series possess completely filled f-orbitals as inner orbitals.

Hence elements heavier than barium all possess f-orbitals.

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What Does The Atomic Radius Change Down A Column Of The Periodic Table
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(c) Assume you have an equilibrium mixture of [A], [B], and [C] at 298K and that the
djyliett [7]

Answer:

Explanation:

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P

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3. The change in enthalpy may be used. If the reaction is exothermic, the heat produced can be thought of as a product. If the reaction is endothermic the heat added can be thought of as a reactant. Additional heat would shift an exothermic reaction back to the reactants but would shift an endothermic reaction to the products. Cooling an exothermic reaction causes the reaction to shift toward the product side; cooling an endothermic reaction would cause it to shift to the reactants’ side.

5. No, it is not at equilibrium. Because the system is not confined, products continuously escape from the region of the flame; reactants are also added continuously from the burner and surrounding atmosphere.

7. Add N2; add H2; decrease the container volume; heat the mixture.

9. (a) ΔT increase = shift right, ΔP increase = shift left; (b) ΔT increase = shift right, ΔP increase = no effect; (c) ΔT increase = shift left, ΔP increase = shift left; (d) ΔT increase = shift left, ΔP increase = shift right.

11. (a)  

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[

CH

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13. (a)  

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15. Only (b)

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Hope this helps :)

3 0
3 years ago
What is the temperature of CO2 gas if the average speed (actually the root-mean-square speed) of the molecules is 750 m/s?
erastova [34]

Answer:

992.302 K

Explanation:

V(rms) = 750 m/s

V(rms) = √(3RT / M)

V = velocity of the gas

R = ideal gas constant = 8.314 J/mol.K

T = temperature of the gas

M = molar mass of the gas

Molar mass of CO₂ = [12 + (16*2)] = 12+32 = 44g/mol

Molar mass = 0.044kg/mol

From

½ M*V² = 3 / 2 RT

MV² = 3RT

K = constant

V² = 3RT / M

V = √(3RT / M)

So, from V = √(3RT / M)

V² = 3RT / M

V² * M = 3RT

T = (V² * M) / 3R

T = (750² * 0.044) / 3 * 8.314

T = 24750000 / 24.942

T = 992.302K

The temperature of the gas is 992.302K

Note : molar mass of the gas was converted from g/mol to kg/mol so the value can change depending on whichever one you use.

3 0
3 years ago
At the heart of the stars, nuclear fusion merges _____ together in the nucleus of atoms to create new elements?
Goshia [24]

Answer:

lighter atoms especially hydrogen

Explanation:

At the heart of the stars, nuclear fusion merges lighter atoms especially hydrogen together in the nucleus of atoms to create new elements.

During nuclear fusion small atomic nuclei combines to form larger ones with the release of a large amount of energy.

The energy released provides the needed temperature for another set of hydrogen atoms to fuse. This process is in turn yields another set of helium atom which releases a lot of energy.

A chain reaction progresses which leads to the formation of new elements.

3 0
3 years ago
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