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kupik [55]
3 years ago
9

Magnetite is a binary compound containing only iron and oxygen. the percent, by weight, of iron is 72.360%. what is the empirica

l formula of magnetite?
a. feo
b. fe2o3
c. fe3o4
d. feo2
Chemistry
2 answers:
hram777 [196]3 years ago
7 0
Answer is: <span>c. Fe</span>₃<span>O</span>₄<span>.
</span>ω(Fe) = 72,360%.
ω(O) = 100% - 72,36% = 27,64%.
For example, if we the mass of compound is 100 g:
m(Fe) = 72,36 g.
n(Fe) = m(Fe) ÷ M(Fe).
n(Fe) = 72,36 g ÷ 55,85 g/mol.
n(Fe) = 1,296 mol.
n(O) = 27,64 g ÷ 16 g/mol.
n(O) = 1,727 mol.
n(Fe) : n(O) = 1,296 mol : 1,727 mol.
n(Fe) : n(O) = 1 : 1,33 or 3 : 4.
Arturiano [62]3 years ago
7 0
<span>Option C. The percentages can be taken for mass. So mass of Iron = 72.360% = 72.36g So mass of Oxygen = 100 - 72.360 = 27.694% = 27.65g Number of moles of Iron = mass/ molar mass = 72.36/ 55.854 = 1.29 Number of moles of Oxygen = 27.65/16 = 1 .728 We shall divide by the smallest So we have 1.29/1.29 = 1 while 1.728/1.29 = 1.33 But 1.33 = 4/3. So we multiply by the lowest common number which happens to be a 3. Hence the empirical formula is Fe3O4.</span>
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Answer:

They went from atoms to oxygen molecule.

Explanation:

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3 years ago
Noah and Nina are 15 m apart in a closed room. Noah says the same sentence twice. The first time, Nina does not hear the sound,
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The air molecules in the compressions of the second wave are denser, so the sound is louder.

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Sound waves are longitudinal waves that travel through a medium like air or water.

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As Noah says the same sentence twice, Nina does not hear the sound the first time but she does hear the sentence the second time.

This happens as the air molecules in the compressions of the second wave are denser. As a result, the sound is louder.

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5 0
1 year ago
How many moles are in 1.05 g of gold (Au)?
Wittaler [7]

Answer:

0.005 mol

Explanation:

Moles is denoted by given mass divided by the molecular mass ,  

Hence ,  

n = w / m

n = moles ,  

w = given mass ,  

m = molecular mass .

From the question ,

w = given mass of Gold = 1.05 g ,

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<u>Hence , moles can be calculated as -</u>

n = w / m = 1.05 g / 197 g/mol = 0.005 mol

7 0
3 years ago
Determine the theoretical yield of HCl if 60.0 g of BC13 and 37.5 g of H20 are reacted according to the following balanced react
Pie

Answer : The theoretical yield of HCl is, 56.1735 grams

Explanation : Given,

Mass of BCl_3 = 60 g

Mass of H_2O = 37.5 g

Molar mass of BCl_3 = 117 g/mole

Molar mass of H_2O = 18 g/mole

Molar mass of HCl = 36.5 g/mole

First we have to calculate the moles of BCl_3 and H_2O.

\text{Moles of }BCl_3=\frac{\text{Mass of }BCl_3}{\text{Molar mass of }BCl_3}=\frac{60g}{117g/mole}=0.513moles

\text{Moles of }H_2O=\frac{\text{Mass of }H_2O}{\text{Molar mass of }H_2O}=\frac{37.5g}{18g/mole}=2.083moles

Now we have to calculate the limiting and excess reagent.

The balanced chemical reaction is,

BCl_3(g)+3H_2O(l)\rightarrow H_3BO_3(s)+3HCl(g)

From the balanced reaction we conclude that

As, 1 mole of BCl_3 react with 3 mole of H_2O

So, 0.513 moles of BCl_3 react with 3\times 0.513=1.539 moles of H_2O

From this we conclude that, H_2O is an excess reagent because the given moles are greater than the required moles and BCl_3 is a limiting reagent and it limits the formation of product.

Now we have to calculate the moles of HCl.

As, 1 mole of BCl_3 react to give 3 moles of HCl

So, 0.513 moles of BCl_3 react to give 3\times 0.513=1.539 moles of HCl

Now we have to calculate the mass of HCl.

\text{Mass of }HCl=\text{Moles of }HCl\times \text{Molar mass of }HCl

\text{Mass of }HCl=(1.539mole)\times (36.5g/mole)=56.1735g

Therefore, the theoretical yield of HCl is, 56.1735 grams

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