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3 years ago

Calculate the number of moles of caco3 (calcium carbonate, or limestone) in a 20.0g sample of this substance

1 answer:

6 0

First calculate for the molar mass of the given formula unit, CaCO₃. This can be done by adding up the product when the number of atom is multiplied to its individual molar mass as shown below.

molar mass of CaCO₃ = (1 mol Ca)(40 g Ca/mol Ca) + (1 mol C)(12 g of C/1 mol of C) + (3 mols of O)(16 g O/1 mol O) = 100 g/mol of CaCO₃

Then, divide the given amount of substance by the calculated molar mass.
number of moles = (20 g)(1 mol of CaCO₃/100 g)
number of moles = 0.2 moles of CaCO₃

Answer: 0.2 moles

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You have used 2.4×102 L of distilled water for a dialysis patient. How many gallons of water is that?

Alinara [238K]

Answer:

63.36gallons

Explanation:

Given:

Volume of water used for dialysis = 2.4 x 10²L

Solution:

We are to convert from liters to gallons.

The conversion factor is shown below:

1L = 0.264gallons

To convert to litre:

since 1L = 0.264gallons

2.4 x 10²L = (2.4 x 10² x 0.264)gallons; 63.36gallons

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3 years ago

If a farmer wants to increase the health of his crops, he could apply a nitrogen-based fertilizer. why is nitrogen important to

Finger [1]

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3 years ago

Which one of these elements is an alkaline earth metal

In-s [12.5K]

The answer to this problem is Beryllium is an alkaline earth metal.

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3 years ago

A student has a 2.19 L bottle that contains a mixture of O 2 , N 2 , and CO 2 with a total pressure of 5.57 bar at 298 K . She k

Sergeeva-Olga [200]

Answer: The partial pressure of oxygen gas is 2.76 bar

Explanation:

To calculate the number of moles, we use the equation given by ideal gas which follows:

$PV=nRT$

where,

P = pressure of the gas = 5.57 bar

V = Volume of the gas = 2.19 L

T = Temperature of the gas = 298 K

R = Gas constant = $0.0831\text{ L bar }mol^{-1}K^{-1}$

n = Total number of moles = ?

Putting values in above equation, we get:

$5.57bar\times 2.19L=n\times 0.0831\text{ L. bar }mol^{-1}K^{-1}\times 298K\\\\n=\frac{5.57\times 2.19}{0.0831\times 298}=0.493mol$

To calculate the mole fraction of carbon dioxide, we use the equation given by Raoult's law, which is:

$p_{A}=p_T\times \chi_{A}$ ........(1)

where,

$p_A$ = partial pressure of carbon dioxide = 0.318 bar

$p_T$ = total pressure = 5.57 bar

$\chi_A$ = mole fraction of carbon dioxide = ?

Putting values in above equation, we get:

$0.318bar=5.57bar\times \chi_{CO_2}\\\\\chi_{CO_2}=\frac{0.381}{5.57}=0.0571$

Mole fraction of a substance is given by:

$\chi_A=\frac{n_A}{n_A+n_B}$

We are given:

Moles of nitrogen gas = 0.221 moles

Mole fraction of nitrogen gas, $\chi_{N_2}=\frac{0.221}{0.493}=0.448$

Calculating the partial pressure of oxygen gas by using equation 1, we get:

Mole fraction of oxygen gas = (1 - 0.0571 - 0.448) = 0.4949

Total pressure of the system = 5.57 bar

Putting values in equation 1, we get:

$p_{O_2}=5.57bar\times 0.4949\\\\p_{O_2}=2.76bar$

Hence, the partial pressure of oxygen gas is 2.76 bar

6 0

3 years ago

Describe how and why the statue of the Sphinx has changed since it was made.

Lyrx [107]

Answer:

I don't know if this will help but. The Great Sphinx has suffered from erosion and vandalism. Hatshepsut's stepson was too young to rule at the time of her husband's death, so she just took the job.

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2 years ago