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3 years ago

To three significant digit,what is the mass percentage of iron in the compound Fe2O3

Chemistry

1 answer:

svlad2 [7]3 years ago

4 0

69.9%

Explanation:

To find the mass percentage of iron in the compound in Fe₂O₃, we would go ahead to express the given molar mass of the iron to that of the compound.

Mass percentage = $\frac{molar mass of Fe}{Molar mass of Fe_{2}O_{3} }$ x 100

Molar mass of Fe = 55.85g/mol

Molar mass of O = 16g/mol

Molar mass of Fe₂O₃ = 2(55.85) + 3(16) = 159.7‬g/mol

Mass percentage = $\frac{2(55.85)}{159.7} x 100$ = 69.94% = 69.9%

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A 0.04328 g sample of gas occupies 10.0-mL at 294.0 K and 1.10 atm. Upon further analysis, the compound is found to be 25.305% C

stepan [7]

Answer:

The molecular formula of the gas sample = $C_2Cl_2$

Lewis structure is shown in the image below.

The geometry around each carbon atom is linear.

Explanation:

Given that:

Temperature = 294.0 K

V = 10.0 mL = 0.01 L ( 1 mL = 0.001 L )

Pressure = 1.10 atm

Using ideal gas equation as:

$PV=nRT$

where,

P is the pressure

V is the volume

n is the number of moles

T is the temperature

R is Gas constant having value = 0.0821 L atm/ K mol

Applying the equation as:

1.10 atm × 0.01 L = n ×0.0821 L atm/ K mol × 294.0 K

⇒n = 0.0004557 mol

Given, mass = 0.04328 g

The formula for the calculation of moles is shown below:

$moles = \frac{Mass\ taken}{Molar\ mass}$

Thus,

$0.0004557\ mole= \frac{0.04328\ g}{Molar\ mass}$

Molar mass of the gas sample = 94.9747 g/mol

Given that:-

% of C = 25.305

Molar mass of C = 12.0107 g/mol

% moles of C = 25.305 / 12.0107 = 2.1069

% of Cl = 74.695

Molar mass of Cl = 35.453 g/mol

% moles of Cl = 74.695 / 35.453 = 2.1069

Taking the simplest ratio for C and Cl as:

2.1069 : 2.1069 = 1 : 1

The empirical formula is = $CCl$

Molecular formulas is the actual number of atoms of each element in the compound while empirical formulas is the simplest or reduced ratio of the elements in the compound.

Thus,

Molecular mass = n × Empirical mass

Where, n is any positive number from 1, 2, 3...

Mass from the Empirical formula = 12 + 35.5 = 47.5 g/mol

Molar mass = 94.9747 g/mol

So,

Molecular mass = n × Empirical mass

94.9747 = n × 47.5

⇒ n = 2

The molecular formula of the gas sample = $C_2Cl_2$

Also,

Valence electrons of carbon = 4

Valence electrons of Chlorine = 7

The total number of the valence electrons = 4*2 + 7*2 = 22

The Lewis structure is drawn in such a way that the octet of each atom in the molecule is complete. So,

The Lewis structure is shown in the image below.

According to the theory, the atoms will form a geometry in such a way that there is minimum repulsion and maximum stability. The carbon atoms are sp hybridized.

So, it is of linear shape.

3 0

4 years ago

Which is the most reactive metal and why?

Gemiola [76]

Answer:

Caesium, the most reactive metal in the periodic table, reacts extremely violently – hence why it can't be demonstrated in a classroom! This can be compared to other common metals, such as iron and copper, which produce no reaction when dropped into water.

Hope this answer is right!

3 0

3 years ago

For the reaction A+B+C→D+E, the initial reaction rate was measured for various initial concentrations of reactants. The followin

erastovalidia [21]

Answer : The initial rate for a reaction will be $3.4\times 10^{-3}Ms^{-1}$

Explanation :

Rate law is defined as the expression which expresses the rate of the reaction in terms of molar concentration of the reactants with each term raised to the power their stoichiometric coefficient of that reactant in the balanced chemical equation.

For the given chemical equation:

$A+B+C\rightarrow D+E$

Rate law expression for the reaction:

$\text{Rate}=k[A]^a[B]^b[C]^c$

where,

a = order with respect to A

b = order with respect to B

c = order with respect to C

Expression for rate law for first observation:

$6.0\times 10^{-5}=k(0.20)^a(0.20)^b(0.20)^c$ ....(1)

Expression for rate law for second observation:

$1.8\times 10^{-4}=k(0.20)^a(0.20)^b(0.60)^c$ ....(2)

Expression for rate law for third observation:

$2.4\times 10^{-4}=k(0.40)^a(0.20)^b(0.20)^c$ ....(3)

Expression for rate law for fourth observation:

$2.4\times 10^{-4}=k(0.40)^a(0.40)^b(0.20)^c$ ....(4)

Dividing 1 from 2, we get:

$\frac{1.8\times 10^{-4}}{6.0\times 10^{-5}}=\frac{k(0.20)^a(0.20)^b(0.60)^c}{k(0.20)^a(0.20)^b(0.20)^c}\\\\3=3^c\\c=1$

Dividing 1 from 3, we get:

$\frac{2.4\times 10^{-4}}{6.0\times 10^{-5}}=\frac{k(0.40)^a(0.20)^b(0.20)^c}{k(0.20)^a(0.20)^b(0.20)^c}\\\\4=2^a\\a=2$

Dividing 3 from 4, we get:

$\frac{2.4\times 10^{-4}}{2.4\times 10^{-4}}=\frac{k(0.40)^a(0.40)^b(0.20)^c}{k(0.40)^a(0.20)^b(0.20)^c}\\\\1=2^b\\b=0$

Thus, the rate law becomes:

$\text{Rate}=k[A]^2[B]^0[C]^1$

Now, calculating the value of 'k' by using any expression.

Putting values in equation 1, we get:

$6.0\times 10^{-5}=k(0.20)^2(0.20)^0(0.20)^1$

$k=7.5\times 10^{-3}M^{-2}s^{-1}$

Now we have to calculate the initial rate for a reaction that starts with 0.75 M of reagent A and 0.90 M of reagents B and C.

$\text{Rate}=k[A]^2[B]^0[C]^1$

$\text{Rate}=(7.5\times 10^{-3})\times (0.75)^2(0.90)^0(0.90)^1$

$\text{Rate}=3.4\times 10^{-3}Ms^{-1}$

Therefore, the initial rate for a reaction will be $3.4\times 10^{-3}Ms^{-1}$

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3 years ago

Please help me people it’s due today at 6:00pm please help me please please

vovangra [49]

Explanation:

gravity if it's incorrect sorry

7 0

3 years ago

Read 2 more answers

a physical property can be observed while the substance remains the same in its chemical composition. true false

sweet [91]

While the material retains its chemical makeup, the physical property may be examined. The given statement is true.

The matter can undergo variations in physical or chemical properties. The physical changes of a matter occur when the matter undergoes changes in its physical properties like changes in the state of matter, weight, color, etc.

But the chemical composition of matter will remain constant if it undergoes a physical change. Whereas in chemical change, the matter undergoes a change in the composition of the substance but there will be no change in the physical properties.

Hence, The assertion is correct in that physical properties can be seen while the substance's chemical makeup stays constant.

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8 0

1 year ago

To three significant digit,what is the mass percentage of iron in the compound Fe2O3​

To three significant digit,what is the mass percentage of iron in the compound Fe2O3