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3 years ago

Answer fast my H.W is hard

Chemistry

1 answer:

Marina86 [1]3 years ago

3 0

Answer: The molality of $MgF_2$ solution is 4.013 m

Explanation:

Molality is defined as the amount of solute expressed in the number of moles present per kilogram of solvent. The units of molarity are mol/kg.

The formula used to calculate molarity:

.....(1)

Given values:

Given mass of $MgF_2$ = 20.0 g

Molar mass of = 62.3 g/mol

Mass of solvent = 80.0 g

Putting values in equation 1, we get:

$\text{Molality of }MgF_2=\frac{20.0\times 1000}{62.3\times 80.0}\\\\\text{Molality of }MgF_2=4.013m$

Hence, the molality of $MgF_2$ solution is 4.013 m

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How many atoms of iodine are in 12.75g of CaI2? Hint. How many Iodines are there in one CaI2 particle?

xenn [34]

Answer:

$5.225x10^{22}atoms\ I$

Explanation:

Hello!

In this case, since 12.75 g of calcium iodide has the following number of moles (molar mass = 293.89 g/mol):

$n_{CaI_2}=12.75gCaI_2*\frac{1molCaI_2}{293.89gCaI_2}=0.0434molCaI_2$

In such a way, since 1 mole of calcium iodide contains 2 moles of atoms of iodine, and one mole of atoms of iodine contains 6.022x10²³ atoms (Avogadro's number), we compute the resulting atoms as shown below:

$atoms\ I=0.0434molCaI_2*\frac{2molI}{1molCaI_2} *\frac{6.022x10^{23}atoms\ I}{1molI} \\\\atoms\ I = 5.225x10^{22}atoms\ I$

Best regards!

4 0

3 years ago

Calculate the number of moles of a gas that is present in a 7.55 L container at 45°C, if the gas exerts a pressure of 725mm Hg.

vovikov84 [41]

Answer: The number of moles of gas present is 0.276 moles

Explanation:

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

PV = nRT

where,

P = Pressure of the gas = 725 mm Hg

V = Volume of the gas = 7.55 L

n = number of moles of gas = ?

R = Gas constant = $62.3637\text{ L.mmHg }mol^{-1}K^{-1}$

T = Temperature of the gas = $45^oC=(45+273)K=318K$

Putting values in above equation, we get:

$725mmHg\times 7.55L=n\times 62.3637\text{ L.mmHg }mol^{-1}K^{-1}\times 318K\\\\n=0.276mol$

Hence, the number of moles of gas present is 0.276 moles

4 0

3 years ago

Calculate the volume of the object immersed in the water in the water in the adjoining figur.

kirza4 [7]

Answer:

100 cm³

Explanation:

Hi there!

Subtract:

400 cm³ - 300 cm³

= 100 cm³

Therefore, the volume of the object is 100 cm³.

I hope this helps!

5 0

3 years ago

An atom has a mass number of 24 and 13 neutrons. What is the atomic number of this atom?

netineya [11]

A=Mass number=24
N=neutrons=13
Z=atomic number.

A=Z+N

24=Z+13
Z=24-13
Z=11

The atomic number is 11, and this atom is sodium.

6 0

3 years ago

Read 2 more answers

In a chemical reaction, substrate molecule A is broken down to form one molecule of product B and one molecule of product C. The

MAVERICK [17]

Answer:

The answer to your question is d. 0.5 M

Explanation:

Data

[A] = 1M

K = 0.5

Concentration of B and C at equilibrium = x

Concentration of A at equilibrium = 1 - x

Equation of equilibrium

k = $\frac{[B][C]}{A}$

Substitution

$0.5 = \frac{[x][x]}{1 - x}$

Simplification

0.5 = $\frac{x^{2}}{1 - x}$

Solve for x

0.5(1 - x) = x²

0.5 - 0.5x = x²

x² + 0.5x - 0.5 = 0

Find the roots x₁ = 0.5 x₂ = -1

There are no negative concentrations so the concentration of A at equilibrium is

[A] = 1 - 0.5

= 0.5 M

4 0

3 years ago