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Anna [14]
2 years ago
7

Which of the following statements about enthalpy is true?

Chemistry
1 answer:
Evgesh-ka [11]2 years ago
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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The graph above shows the changes in temperature recorded for the 2.00 l of h2o surrounding a constant-volume container in which
Otrada [13]

Answer:

25.2 kJ

Explanation:

The complete question is presented in the attached image to this answer.

Note that, the heat gained by the 2.00 L of water to raise its temperature from the initial value to its final value comes entirely from the combustion of the benzoic acid since there are no heat losses to the containing vessel or to the environment.

So, to obtained the heat released from the combustion of benzoic acid, we just calculate the heat required to raise the temperature of the water.

Q = mCΔT

To calculate the mass of water,

Density = (mass)/(volume)

Mass = Density × volume

Density = 1 g/mL

Volume = 2.00 L = 2000 mL

Mass = 1 × 2000 = 2000 g

C = specific heat capacity of water = 4.2 J/g.°C

ΔT = (final temperature) - (Initial temperature)

From the graph,

Final temperature of water = 25°C

Initial temperature of water = 22°C

ΔT = 25 - 22 = 3°C

Q = (2000×4.2×3) = 25,200 J = 25.2 kJ

Hope this Helps!!!

6 0
3 years ago
Which of the following measurements is equal to 150 dL?
MrRissso [65]
This is a case of metric system of measurements. The scale of the metric system only differs by a factor of 10. The scale (from greatest to least) is kiloliter, hectoliter, dekaliter, liter, deciliter, centiliter and milliliter. If the unit is 150 dL, and you want to find the equivalent dkL measurement, just move the decimal point 2 decimals places to the left (just follow the scale). The same procedure is done for the other metric units.

150 dL = 1.5 dkL
150 dL = 15 L
150 dL = 1,500 cL
150 dL = 15,000 mL

From the choices, the answer is letter C.
6 0
3 years ago
Please Help! I just started balancing equations and my teacher gave me this. Thanks in advance! :D
Alenkasestr [34]
So you need to put numbers before each compound to make sure there are the exact same number of elements on each side. If you put a 4 before NH4 there are 4 Nitrogen and now 16 hydrogen. I just played around with numbers and guessed until I got them even.
8 0
3 years ago
Read 2 more answers
Water travels through many different pathways within the hydrologic cycle. For example, water vapor in the atmosphere could cond
Anit [1.1K]
It would most likely be D because that’s how most of the things would be processed but sorry if I’m wrong.
5 0
2 years ago
Read 2 more answers
Three identical flasks contain three different gases at standard temperature and pressure. Flask A contains CH4, flask B contain
erastovalidia [21]

Answer:

FLASK B WHICH CONTAINS CO2 HAS THE HIGHEST NUMBER OF MOLECULES AS IT CONTAINS THE HIGHEST MOLECULAR MASS OF 44 G/MOL.

Explanation:

Flask A contains CH4

Flask B contaims CO2

Flask C contains N2

To know the flask containing the largest number of molecules, we find the molar mass of the molecules in the flask and the largest is the one with the highest number of the relative molecular mass.

Molecular Mass of CH4 (C = 12, H =1) = ( 12 + 1*4) g/mol

= 16 g/mol

Molecular mass of CO2 (C= 12, 0= 16) = (12 + 16*2) g/mol

= 12 + 32 g/mol

= 44 g/mol

Molecular mass of N2 (N=14) = 14 * 2 g/mol

= 28 g/mol

Hence, the flask with the largest number of molecules is the flask with the highest relative molecular mass. The highest molecular mass is 44 g/mol and it is for the gas CO2 in Flask B.

So therefore, Flask B has the highest number of molecules in it.

4 0
2 years ago
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