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3 years ago

Calculate the molar solubility of CaF2 in a 0.25 m solution of NaF(aq).

Chemistry

1 answer:

Kipish [7]3 years ago

8 0

Answer:

6.4 × 10^-10 M

Explanation:

The molar solubility of the ions in a compound can be calculated from the Ksp (solubility constant).

CaF2 will dissociate as follows:

CaF2 ⇌Ca2+ + 2F-

1 mole of Calcium ion (x)

2 moles of fluorine ion (2x)

NaF will also dissociate as follows:

NaF ⇌ Na+ + F-

Where Na+ = 0.25M

F- = 0.25M

The total concentration of fluoride ion in the solution is (2x + 0.25M), however, due to common ion effect i.e. 2x<0.25, 2x can be neglected. This means that concentration of fluoride ion will be 0.25M

Ksp = {Ca2+}{F-}^2

Ksp = {x}{0.25}^2

4.0 × 10^-11 = 0.25^2 × x

4.0 × 10^-11 = 0.0625x

x = 4.0 × 10^-11 ÷ 6.25 × 10^-2

x = 4/6.25 × 10^ (-11+2)

x = 0.64 × 10^-9

x = 6.4 × 10^-10

Therefore, the molar solubility of CaF2 in NaF solution is 6.4 × 10^-10M

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What is the relationship between ionization energy and the

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Ionization energy is directly proportional to elements location on the periodic table

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4 years ago

Sulfur undergoes combustion to yield sulfur trioxide by the following reaction equation:

12345 [234]

Answer:

Therefore, the amount of heat produced by the reaction of 42.8 g S = (-5.2965 × 10²) kJ = (-5.2965 × 10⁵) J

Explanation:

Given reaction: 2S + 3O₂ → 2 SO₃

Given: The enthalpy of reaction: ΔH = - 792 kJ

Given mass of S: w₂ = 42.8 g, Molar mass of S: m = 32 g/mol

In the given reaction, the number of moles of S reacting: n = 2

As, Number of moles: $n = \frac{mass\: (w_{1})}{molar\: mass\: (m)}$

∴ mass of S in 2 moles of S: $w_{1} = n \times m = 2\: mol \times 32\: g/mol = 64\: g$

Given reaction: 2S + 3O₂ → 2 SO₃

In this reaction, the limiting reagent is S

⇒ 2 moles S produces (- 792 kJ) heat.

or, 64 g of S produces (- 792 kJ) heat.

∴ 42.8 g of S produces (x) amount of heat

⇒ The amount of heat produced by 42.8 g S:

$x = \frac{(- 792\: kJ) \times 42.8\: g}{64\: g} = (-529.65)\: kJ$

$\Rightarrow x = (-5.2965 \times 10^{2})\: kJ = (-5.2965 \times 10^{5})\: J$

$(\because 1 kJ = 10^{3} J)$

Therefore, the amount of heat produced by the reaction of 42.8 g S = (-5.2965 × 10²) kJ = (-5.2965 × 10⁵) J

8 0

3 years ago

While a certain isotope decays, it emits photons. What kind of decay is happening?

gizmo_the_mogwai [7]

The correct answer is Gamma decay. It happens after beta and alpha decay because what's left after those two can enter a new process of gamma decay. This releases gamma rays which is a more complex term for the photons that you mentioned before. These rays can be dangerous for humans so care not to get caught in them.

6 0

3 years ago

Read 2 more answers

What do you look at to tell the reactivity of an atom?

tia_tia [17]

Answer:

The number of electrons in the outermost shell of an atom determines its reactivity. Noble gases have low reactivity because they have full electron shells. Halogens are highly reactive because they readily gain an electron to fill their outermost shell.

Explanation:

I hope this helped!

8 0

3 years ago

if I have 22.1 grams of CO2 gas at -188 degrees Celsius and 165 ml what is the pressure of the gas in kPa

Harman [31]

Answer:

P = 2.145kPa

Explanation:

Mass = 22.1g

Molar mass of CO2 = 44g/mol

Vol = 165mL = 0.165L

T = -188°C = (-188 + 273.15)K = 85.15K

R = 8.314J/mol.K

From ideal gas equation,

PV = nRT

P = pressure of the ideal gas

V = volume the gas occupies

n = number of moles if the gas

R = ideal gas constant

T = temperature of the gas

n = number of moles

n = mass / molar mass

n = 22.1 / 44 = 0.50moles

PV = nRT

P = nRT/ V

P = (0.5 × 8.314 × 85.15) / 0.165

P = 2145.26Pa = 2.145kPa

Pressure of the gas is 2.145kPa

6 0

3 years ago