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3 years ago

A hydrate of CoCl2 with a mass of 6.00 g is heated strongly. After cooling, the mass of the anhydrate is 3.27 g.

1 answer:

ivann1987 [24]3 years ago

5 0

A hydrate is a substance that contains water or its constituent elements. When this substance is heated, water is evaporated leaving an unhydrate. From this sample, the amount of water present would be equal to 2.73 g. Hope this answers the question. Have a nice day.

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A scientist measures the standard enthalpy change for the following reaction to be -327.2 kJ : P4O10(s) 6 H2O(l)4H3PO4(aq) Based

OleMash [197]

Answer:

ΔH°f P4O10(s) = - 3115.795 KJ/mol

Explanation:

P4O10(s) + 6H2O(l) ↔ 4H3PO4(aq)
ΔH°rxn = ∑νiΔH°fi

∴ ΔH°rxn = - 327.2 KJ

∴ ΔH°f H2O(l) = - 285.84 KJ/mol

∴ ΔH°F H3PO4(aq) = - 1289.5088 KJ/mol

⇒ ΔH°rxn = (4)(- 1289.5088) - (6)(- 285.84) - ΔH°f P4O10(s) = - 327.2 KJ

⇒ ΔH°f P4O10(s) = - 5158.035 + 1715.04 + 327.2

⇒ ΔH°f P4O10(s) = - 3115.795 KJ/mol

5 0

3 years ago

Which of the following are true of phases?Check all that apply.A.The particles in a liquid are in a fixed location.B.Gases have

saw5 [17]

Answer:

The answers are options b , c and d.

Hope this helps.

7 0

3 years ago

Benzene has a specific gravity of 0.88. if it was spilled in a river what would it do?

Gelneren [198K]

As we know,
Density of Benzene = 876 Kg/m³
And,
Density of Water = 997 Kg/m³
So,
Specific Gravity is calculated as,

Specific Gravity = Density of Benzene / Density of Water

Specific Gravity = 876 Kg/m³ / 997 Kg/m³

Specific Gravity = 0.878

Every object having specific gravity less than 1 will float on water and if value is greater than 1 then it will sink.

Benzene being non-polar in nature does not mix with water and due to less density it will float on the surface of water.

4 0

3 years ago

. Sulfur dioxide can be produced in the laboratory by the reaction of hydrochloric acid and a sulfite salt such as sodium sulfit

shutvik [7]

Answer:

Mass of SO₂ can be made from 25.0 g of Na₂SO₃ and 22 g of HCl = 12.672 g

Explanation:

SO₂( sulfur dioxide) can be produced in the lab. by the reaction of hydrochloric acid & sulphite salt such as sodium.

the balanced chemical equation is as follows

Na₂SO₃ + 2 HCl → 2 NaCl + SO₂ + H₂O

Moles of Na₂SO₃ = $\frac{Mass}{Molecular mass} =\frac{25}{126} = 0.198$

Moles of HCl = $\frac{mass}{molecular mass}=\frac{22}{36.5}= 0.6$

using mole ratio method to find limiting reagent

For sodium sulfite $\frac{mole}{stoichiometry} = \frac{0.198}{1}= 0.198$

for HCl $\frac{mole}{stoichiometry} = \frac{0.6}{2}= 0.3$

since sodium sulfite is limiting reactant for above chemical reaction

1 mole of Na₂SO₃ produce 1 mole of SO₂

0.198 mole of Na₂SO₃ produce 0.198 mole of SO₂

∴ Mass of SO₂ produce = mole x molar mass of SO₂

= 0.198 x 64

= 12.672 g

8 0

3 years ago

The estimated heat of vaporization of diethyl ether using the Chen's rule is A. 29.7 KJ/mol B. 33.5 KJ/mol C. 26.4 KJ/mol D. 36.

Brums [2.3K]

Answer:

C. 26.4 kJ/mol

Explanation:

The Chen's rule for the calculation of heat of vaporization is shown below:

$\Delta H_v=RT_b\left [ \frac{3.974\left ( \frac{T_b}{T_c} \right )-3.958+1.555lnP_c}{1.07-\left ( \frac{T_b}{T_c} \right )} \right ]$

Where,

$\Delta H_v$ is the Heat of vaoprization (J/mol)

$T_b$ is the normal boiling point of the gas (K)

$T_c$ is the Critical temperature of the gas (K)

$P_c$ is the Critical pressure of the gas (bar)

R is the gas constant (8.314 J/Kmol)

For diethyl ether:

$T_b=307.4\ K$

$T_c=466.7\ K$

$P_c=36.4\ bar$

Applying the above equation to find heat of vaporization as:

$\Delta H_v=8.314\times307.4 \left [ \frac{3.974\left ( \frac{307.4}{466.7} \right )-3.958+1.555ln36.4}{1.07-\left ( \frac{307.4}{466.7} \right )} \right ]$

$\Delta H_v=26400 J/mol$

The conversion of J into kJ is shown below:

1 J = 10⁻³ kJ

Thus,

$\Delta H_v=26.4 kJ/mol$

Option C is correct

6 0

3 years ago