Election configuration for carbon

How many moles of solute are contained in a 250.0 ml solution with a concentration of 2.5 M?

larisa [96]

The unit M means that mole/L, So first change the unit of solution volume to L which is 0.25 L. So the mole of solute is 2.5*0.25=0.625 mol.

7 0

3 years ago

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Iron has many isotopes but only 4 are found in significant amounts in naturally found mixtures. The amounts by mass percent are:

AnnZ [28]

Answer:

The average mass of iron to be is 54.76 amu.

Explanation:

Formula used to calculate average atomic mass follows:

$\text{Average atomic mass }=\sum_{i=1}^n\text{(Atomic mass of an isotopes)}_i\times \text{(Fractional abundance})_i$

1)

Mass of Fe-54 isotope = 53.9396 amu

Percentage abundance of Fe-54 = 5.845%

Fractional abundance of Fe-54 = 0.05845

2)

Mass of Fe-56 isotope = 55.9349 amu

Percentage abundance of Fe-56 = 91.754 %

Fractional abundance of Fe-56= 0.91754

3)

Mass of Fe-57 isotope = 56.9354 amu

Percentage abundance of Fe-57 = 2.119%

Fractional abundance of Fe-57 = 0.002119

4)

Mass of Fe-58 isotope = 57.9333 amu

Percentage abundance of Fe-58 = 0.282%

Fractional abundance of Fe-58 = 0.00282

Average atomic mass of iron :

$=53.9396 amu\times 0.05845+55.9349 amu\times 0.91754 +56.9354 amu\times 0.002119 + 57.9333 amu\times 0.00282=54.76 amu$

The average mass of iron to be is 54.76 amu.

5 0

3 years ago

The density of gas particles in a section of Earth’s atmosphere decreases. Which of the following is the most likely explanation

Bad White [126]

<span>This is due to the fact that the air pressure in that certain section of Earth’s atmosphere decreased. As density of gas particles decreases as air pressure decreases. Therefore, density of gas particles and air pressure have a direct relationship. An increase in air pressure would then effect to an increase in gas particles. </span>

6 0

3 years ago

30 points

vfiekz [6]

The molecular weight for Calcium Chloride Dihydrate (CaCl2•2H20) is 2H2O.

mass of 64g/mol = 256.52 g/mol
mass of 11g/mol = 26.981538 g/mol
mass of 147g/mol= 146.9149 g/mol
258g/mol = 258.09843 g/mol

8 0

4 years ago

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How many moles are in 2.5 g of N2<br> O 0089 moles<br> 0.18 moles<br> 13 moles<br> 11 moles

alexgriva [62]

<h2>PRACTICE MULTIPLE CHOICE QUESTIONS FROM UNIT 10</h2>

<h3>1.) A cylinder is filled with 2.00 moles of nitrogen, 3.00 moles of argon, and 5.00 moles of helium. If</h3>

the gas mixture is at STP, what is the partial pressure of the argon?

(A) 152 torr (B) 228 torr (C) 380. torr (D) 760. torr

2.) Compared to the average kinetic energy of 1 mole of water at 0 oC, the average kinetic energy

of 1 mole of water at 298 K is

(A) the same, and the number of molecules is the same

(B) the same, but the number of molecules is greater

(C) greater, and the number of molecules is greater

(D) greater, but the number of molecules is the same

3.) If the pressure on a given mass of gas in a closed system is increased and the temperature

remains constant, the volume of the gas will

(A) decrease (B) increase (C) remain the same

4.) Which gas has approximately the same density as C2H6 at STP?

(A) NO (B) NH3 (C) H2S (D) SO2

5.) At a temperature of 273 K, a 400. milliliter gas sample has a pressure of 760. millimeters of

mercury. If the pressure is changed to 380. millimeters of mercury, at which temperature will

this gas sample have a volume of 551 milliliters?

(A) 100 K (B) 188 K (C) 273 K (D) 546 K

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3 0

3 years ago

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