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3 years ago

Determine the empirical formula for a compound that is found to contain

Chemistry

1 answer:

Sphinxa [80]3 years ago

7 0

Answer:

The empirical formula is PCl3

Explanation:

Mass of P is 30.97 g, thus 1.523 g of P equivalent to 0.05 moles of P

Mass of Cl is 35.45 g, thus 5.228 g of Cl equivalent to 0.15 moles of Cl

Therefore moles of P : moles of Cl = 0.05:0.15 = 1:3

Therefore the empirical formula, PCl3

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daniel has a sample of pure copper. its mass is 89.6 grams (g), and its volume is 10 cubic centimeters (cm3). what’s the density

77julia77 [94]

D = mass / volume

d = 89.6 / 10

d = 8.96 g/cm³

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3 years ago

Be sure to answer all parts. Styrene is produced by catalytic dehydrogenation of ethylbenzene at high temperature in the presenc

svlad2 [7]

Answer:

a) ΔHºrxn = 116.3 kJ, ΔGºrxn = 82.8 kJ, ΔSºrxn = 0.113 kJ/K

b) At 753.55 ºC or higher

c )ΔG = 1.8 x 10⁴ J

K = 8.2 x 10⁻²

Explanation:

a) C6H5−CH2CH3 ⇒ C6H5−CH=CH2 + H₂

ΔHf kJ/mol -12.5 103.8 0

ΔGºf kJ/K 119.7 202.5 0

Sº J/mol 255 238 130.6*

Note: This value was not given in our question, but is necessary and can be found in standard handbooks.

Using Hess law to calculate ΔHºrxn we have

ΔHºrxn = ΔHfº C6H5−CH=CH2 + ΔHfº H₂ - ΔHºfC6H5−CH2CH3

ΔHºrxn = 103.8 kJ + 0 kJ - (-12.5 kJ)

ΔHºrxn = 116.3 kJ

Similarly,

ΔGrxn = ΔGºf C6H5−CH=CH2 + ΔGºfH₂ - ΔGºfC6H5CH2CH3

ΔGºrxn= 202.5 kJ + 0 kJ - 119.7 kJ = 82.8 kJ

ΔSºrxn = 238 J/mol + 130.6 J/mol -255 J/K = 113.6 J/K = 0.113 kJ/K

b) The temperature at which the reaction is spontaneous or feasible occurs when ΔG becomes negative and using

ΔGrxn = ΔHrxn -TΔS

we see that will happen when the term TΔS becomes greater than ΔHrxn since ΔS is positive , and so to sollve for T we will make ΔGrxn equal to zero and solve for T. Notice here we will make the assumption that ΔºHrxn and ΔSºrxn remain constant at the higher temperature and will equal the values previously calculated for them. Although this assumption is not entirely correct, it can be used.

0 = 116 kJ -T (0.113 kJ/K)

T = 1026.5 K = (1026.55 - 273 ) ºC = 753.55 ºC

c) Again we will use

ΔGrxn = ΔHrxn -TΔS

to calculate ΔGrxn with the assumption that ΔHº and ΔSºremain constant.

ΔG = 116.3 kJ - (600+273 K) x 0.113 kJ/K = 116.3 kJ - 873 K x 0.113 kJ/K

ΔG = 116.3 kJ - 98.6 kJ = 17.65 kJ = 1.8 x 10⁴ J ( Note the kJ are converted to J to necessary for the next part of the problem )

Now for solving for K, the equation to use is

ΔG = -RTlnK and solve for K

- ΔG / RT = lnK ∴ K = exp (- ΔG / RT)

K = exp ( - 1.8 x 10⁴ J /( 8.314 J/K x 873 K)) = 8.2 x 10⁻²

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3 years ago

What is the reaction if you mix vinegar Ajax bleach together.

Fantom [35]

The combination sounds like it'd be a powerful disinfectant, but the two should never be mixed. "Together, they produce chlorine gas, which even at low levels, can cause coughing, breathing problems, and burning, watery eyes," says Forte.

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3 years ago

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Are metal and non-metal elements typically ionically bonded? Explain.

victus00 [196]

Answer: Yes, metals and non-metals forms ionic bonds.

Explanation:

Ionic bond is defined as the bond which is formed by complete transfer of electrons from one atom to another atom.

The atom which looses the electron is known as electropositive atom and the atom which gains the electron is known as electronegative atom. This bond is usually formed between a metal and a non-metal.

For Example: Formation of sodium chloride

Sodium is a metal and is the 11th element of periodic table having electronic configuration of $[Ne]3s^1$

To form $Na^{+}$ ion, this element will loose 1 electron.

Chlorine is a non-metal and is the 17th element of periodic table having electronic configuration of $[Ne]3s^23p^5$ .

To form $Cl^{-}$ ion, this element will gain 1 electron.

By criss-cross method, the oxidation state of the ions gets exchanged and they form the subscripts of the other ions. This results in the formation of a neutral compound.

So, the compound formed between sodium and chlorine atom is NaCl

Hence, metals and non-metals forms ionic bonds.

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Mashcka [7]

Number of moles:

n = sample mass / molar mass

n = 15.00 / 74.6

n = 0.2010 moles of KCl

Therefore:

Molarity = moles / Volume

0.1107 = 0.2010 / V

V = 0.2010 / 0.1107

V = 1.815 L

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4 years ago

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