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3 years ago

Why is it important to determine the qcalorimeter before determining the qmetal?

2 answers:

8 0

In order to determine the heat absorbed or given by a metal it is important to determine the heat loss or gained by calorimeter

If we dip a hot metal piece in a calorimeter, it will lose energy which will be absorbed by calorimeter

The heat absorbed by calorimeter = heat loss by metal

the heat absorbed by calorimeter = heat capacity of calorimter X change in temperature

so we should have the value of heat absorbed by calorimeter which will be equal to the heat loss by metal

heat loss by metal = mass of metal X specific heat of metal X change in temperature

thus we can calculate the specific heat of metal.

nataly862011 [7]3 years ago

7 0

<span>To find the enthalpy change per mole of a substance A in a reaction between two substances A and B, the substances are added to a calorimeter and the initial and final temperatures (before the reaction started and after it has finished) are noted</span>

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A solution contains [Ba2+] = 5.0 × 10−5 M, [Zn2+] = 2.0 × 10−7 M, and [Ag+] = 3.0 × 10−5 M. Sodium oxalate (Na2C2O4) is slowly a

Jet001 [13]

Answer:

BaC₂O₄, then ZnC₂O₄, then Ag₂C₂O₄

Explanation:

1. Calculate the equilibrium concentrations of oxalate ion

Let [C₂O₄²⁻] = c

(a) Barium oxalate

BaC₂O₄ ⇌ Ba²⁺ + C₂O₄²⁻

E/mol·L⁻¹: 5.0 × 10⁻⁵ c

Ksp = [Ba²⁺][C₂O₄²⁻] = 5.0 × 10⁻⁵c = 1.5 × 10⁻⁸

c = (1.5 × 10⁻⁸)/(5.0 × 10⁻⁵) = 3.0 × 10⁻⁴ mol·L⁻¹

(b) Zinc oxalate

ZnC₂O₄ ⇌ Zn²⁺ + C₂O₄²⁻

E/mol·L⁻¹: 2.0 × 10⁻⁷ c

Ksp = [Zn²⁺][C₂O₄²⁻] = 2.0 × 10⁻⁷c = 1.35 × 10⁻⁹

c = (1.35 × 10⁻⁹)/(2.0 × 10⁻⁷) = 6.8 × 10⁻³ mol·L⁻¹

(c) Silver oxalate

Ag₂C₂O₄ ⇌ 2Ag⁺ + C₂O₄²⁻

E/mol·L⁻¹: 3.0 × 10⁻⁵ c

Ksp = [Ag⁺]²[C₂O₄²⁻] = (3.0× 10⁻⁵)²c = 9.0 × 10⁻¹⁰c = 1.1 × 10⁻¹¹

c = (1.1 × 10⁻¹¹)/(9.0 × 10⁻¹⁰) = 0.012 mol·L⁻¹

2. Decide the order of precipitation

BaC₂O₄ will precipitate when c > 3.0 × 10⁻⁴ mol·L⁻¹

ZnC₂O₄ will precipitate when c > 6.8 × 10⁻³ mol·L⁻¹

Ag₂C₂O₄ will precipitate when c > 0.028 mol·L⁻¹

This happens to be the order of increasing concentration of oxalate ion.

The order of precipitation is

BaC₂O₄, then ZnC₂O₄, then Ag₂C₂O₄

4 0

3 years ago

When a kettle is placed on the stove and water begins to boil, the hotter water at the bottom begins to rise and the

My name is Ann [436]

Answer:

The cooler water is denser

Explanation:

Convection drives the boiling of water placed on a stove in a kettle.

During convection, heat is circulated by density differences in portions of a fluid.

Convection is a form of heat transfer in fluids especially gas and liquid.

In boiling water, the heat is supplied to the base of the stove.
The water at the bottom on heat becomes lighter as the molecules gain more kinetic energy.
The colder part of the water on top sinks to replace the less dense on below.
This exchange sets up convection cells in the kettle.

3 0

2 years ago

Read 2 more answers

Convert from moles to particles 6.02x1023 particles 1 mole Question 2. 2.7 moles of lithium Question 3. 1.8 moles of sodium chlo

spayn [35]

Considering the definition of Avogadro's number:

the number of molecules of lithium is 1.62621×10²⁴ molecules.
the number of molecules of sodium chloride is 1.08414×10²⁴ molecules.

<h3>Definition of Avogadro's number</h3>

Avogadro's Number or Avogadro's Constant is called the number of particles that make up a substance (usually atoms or molecules) and that can be found in the amount of one mole of said substance. Its value is 6.023×10²³ particles per mole. Avogadro's number applies to any substance.

<h3>Amount of molecules in this case</h3>

You can apply the following rule of three, considering the Avogadro's number: If 1 mole of lithium contains 6.023×10²³ molecules, 2.7 moles of lithium contains how many molecules?

amount of molecules of lithium= (6.023×10²³ molecules × 2.7 moles)÷1 mole

<u><em>amount of molecules of lithium=1.62621×10²⁴ molecules</em></u>

Finally, the number of molecules of lithium is 1.62621×10²⁴ molecules.

On the other hand you can apply the following rule of three, considering the Avogadro's number: If 1 mole of sodium chloride contains 6.023×10²³ molecules, 1.8 moles of sodium chloride contains how many molecules?

amount of molecules of sodium chloride= (6.023×10²³ molecules × 1.8 moles)÷1 mole

<u><em>amount of molecules of sodium chloride=1.08414 ×10²⁴ molecules</em></u>

Finally, the number of molecules of sodium chloride is 1.08414×10²⁴ molecules.

Learn more about Avogadro's Number:

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brainly.com/question/1445383

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2 years ago

Percocet contains oxycodone at varying strengths.Every strength also contains 325 mg of

Marat540 [252]

5.56 Rhats The right answer

6 0

3 years ago

What types of questions can be answered through science and what questions are beyond the boundaries of science? Be specific and

Anna [14]

The questions tha science can answer are those can be tested to try to find a definite answer.

For example, whether light is wave or particle is matter of science.

Questions that cannot have a definite answer are the field of religion or philosophy, and are out of the boundaries of science.

For example, does a criminal deserve the punishment of not seeing light? It is a moral question, which to be responded needs the intervention of philosophy and that could have different anwers at different times and in different societies.

3 0

3 years ago