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3 years ago

Which of the following statements about enthalpy is true?

1 answer:

7 0

Answer: A chemical process must occur and then changes between the state of the reactants and the state of the products can be determined

Explanation: Enthalpy represents the sum of the energy of the system with the product of the pressure and volume of that system. As a thermodynamic property, it expresses the ability to release heat from the system. In fact, enthalpy tells us how much heat and work has changed during the chemical reaction under constant pressure. When measuring, measurements of the difference in enthalpy between the two states of the system is performed, before and after the chemical reaction, since total enthalpy can not be measured. This measurement of the enthalpy change can tell us, for example, whether the heat was released from the system during the reaction, or the system absorbed the heat.

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A chemist heats the block of copper as shown in the interactive, then places the metal sample in a cup of oil at 25.00 °C instea

Mazyrski [523]

When the oil is added to the heated copper, the energy in the system is

conserved.

The mass of the oil in the cup, is approximately 64.73 grams.

Reasons:

The question parameters are;

Temperature of the oil in the cup = 25.00°C

Final temperature of the oil and copper, T₂ = 27.33 °C

Specific heat of copper, c₂ = 0.387 J/(g·°C)

Specific heat capacity of oil, c₁ = 1.74 J/(g·°C)

Required:

The mass of oil in the cup.

Solution:

The mass of the copper, m₂ = 17.920 g

Temperature of copper after heating, T₂ = 65.17°C

Temperature of the copper after being placed in the cup of oil, T₂ = 27.33°C

Heat lost by copper = Heat gained by the oil

m₂·c₂·(T₂ - T₃) = m₁·c₁·(T₃ - T₁)

Therefore, we get;

17.920 × 0.387 × (65.17 - 27.33) = m₁ × 1.74 × (27.33 - 25)

262.4219136 = 4.0542·m₁

m₁ ≈ 64.73

The mass of the oil in the cup, m₁ ≈ 64.73 g

Learn more here:

brainly.com/question/21406849

Possible part of the question obtained from a similar question online, are;

The mass of the copper, m₂ = 17.920 g

Temperature of copper after heating = 65.17°C

6 0

2 years ago

Atmospheric pressure yesterday was given as 0.875 atm. Express this pressure in units of torr and also in kilopascals (kPa), res

Aneli [31]

This problem is about conversion and dimensional analysis. Important information to know:
1 atm = 760 torr = 101.325 kPa

For atm to torr conversion:

0.875 atm * (760 torr / 1 atm) = 665 torr

For atm to kPa conversion:

0.875 atm * (101.325 kPa / atm) = 88.7 kPa

Thus the answer is b) 665 torr and 88.7 kPa

5 0

3 years ago

An exothermic reaction has a positive enthalpy (heat) of reaction.(T/F)

mestny [16]

Answer:

True.

Explanation:

An exothermic reaction has a positive enthalpy (heat) of reaction. However, it can be negative in some circumstances.

5 0

3 years ago

Read 2 more answers

Explain why different liquids boil at the different temperatures

Gennadij [26K]

The boiling point of the fluid depends on the intermolecular forces between the fluid atoms and molécules, as these forces must be disrupted to switch from a fluid to a gas. The stronger the intermolecular forces, the greater the point of boiling.

4 0

2 years ago

Read 2 more answers

If 200.4g of water is mixed with 101.42g of salt the mass of the final solution would be reported as

d1i1m1o1n [39]

Answer:

301.8 g

Explanation:

We prepare a solution with 200.4 g of water (solvent) and 101.42 g of salt (solute). The mass of the solution is equal to the sum of the mass of the solvent and the mass of the solute.

m(solution) = m(solute) + m(solvent)

m(solution) = 200.4 g + 101.42 g

m(solution) = 301.8 g (we round-off to one decimal according to the significant figures rules)

8 0

2 years ago