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3 years ago

What is the empirical formula of the compound that is 25.3% magnesium and 74.7% chlorine

Chemistry

1 answer:

Margarita [4]3 years ago

4 0

Answer: $MgCl_2$

Explanation:

25.3% Mg

74.7% Cl

First step: change % to g

25.3g Mg

74.7g Cl

Second step: calculate g/mol of each compound. You can do this by using the atomic mass.

$25.3gMg(\frac{1mol}{24.30g})=1.04mol$

$74.7gCl(\frac{1mol}{35.45g} )=2.11mol$

Third step: determine the lowest number and divide everything by it. Of the result, extract whole number only.

$Mg=\frac{1.04}{1.04} =1$

$Cl=\frac{2.11}{1.04}=2$

Fourth step: Write each compound with their respective number below.

This empirical formula should be: $MgCl_2$

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Liquid hexane

maks197457 [2]

Answer: The mass of $H_2O$ produced is 2.52 g

Explanation:

The number of moles is defined as the ratio of the mass of a substance to its molar mass. The equation used is:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$ ......(1)

For hexane:

Given mass of hexane = 1.72 g

Molar mass of hexane = 86.18 g/mol

Putting values in equation 1, we get:

$\text{Moles of hexane}=\frac{1.72g}{86.18g/mol}=0.020mol$

For oxygen gas:

Given mass of oxygen gas = 8.0 g

Molar mass of oxygen gas= 32 g/mol

Putting values in equation 1, we get:

$\text{Moles of water}=\frac{8.0g}{32g/mol}=0.25mol$

The chemical equation for the combustion of hexane follows:

$2C_6H_{14}+19O_2\rightarrow 12CO_2+14H_2O$

By stoichiometry of the reaction:

If 2 moles of hexane reacts with 19 moles of oxygen gas

So, 0.020 moles of hexane will react with = $\frac{19}{2}\times 0.020=0.19mol$ of oxygen gas

As the given amount of oxygen gas is more than the required amount. Thus, it is present in excess and is considered as an excess reagent.

Thus, hexane is considered a limiting reagent because it limits the formation of the product.

By the stoichiometry of the reaction:

If 2 moles of hexane produces 14 moles of $H_2O$

So, 0.020 moles of hexane will produce = $\frac{14}{2}\times 0.020=0.14mol$ of $H_2O$

We know, molar mass of $H_2O$ = 18 g/mol

Putting values in above equation, we get:

$\text{Mass of }H_2O=(0.14mol\times 18g/mol)=2.52g$

Hence, the mass of $H_2O$ produced is 2.52 g

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3 years ago

What is the mass in grams of 0.7350 moles of sodium?

Alik [6]

Answer:

Explanation:

1 mol of sodium = 23 grams (use the number on your periodic table).

0.7350 mol sodium = x

Cross multiply

1*x = 0.7350 * 23

x = 16.905

You will get slightly less than this, depending on your periodic table. But the method will be the same.

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2 years ago

The energy released from 1 gram of uranium is more than 1 million times greater than the energy released from 3 grams of coal. T

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The energy released from 1 gram of uranium is more than 1 million times greater than the energy released from 3 grams of coal is True.

Explanation:

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In the given example, it is obvious that the energy released from 1 gram of uranium is more than that of the energy released from 3 grams of coal because the amount of energy released during nuclear fission is millions of times more efficient per mass than that of coal considering only $\frac{1}{10}^{th}$ part of the original nuclei is converted to energy.

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