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3 years ago

Why might it be important in a real life situation, to know if a chemical or physical change occurred?

1 answer:

6 0

There are four signs that a chemical reaction has occurred: a change in color, a change in temperature, formation of a gas or formation of a precipitate. A precipitate is a solid that forms when two liquid solutions are mixed. As matter changes in a chemical reaction, it can either absorb or release energy.

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A chemist fills a reaction vessel with 9.20 atm nitrogen monoxide (NO) gas, 9.15 atm chlorine (CI) gas, and 7.70 atm nitrosyl ch

ivanzaharov [21]

Answer:

The reactions free energy $\Delta G = -49.36 kJ$

Explanation:

From the question we are told that

The pressure of (NO) is $P_{NO} = 9.20 \ atm$

The pressure of (Cl) gas is $P_{Cl} = 9.15 \ atm$

The pressure of nitrosly chloride (NOCl) is $P_{(NOCl)} = 7.70 \ atm$

The reaction is

$2NO_{(g)} + Cl_2 (g)$ ⇆ $2 NOCl_{(g)}$

From the reaction we can mathematically evaluate the $\Delta G^o$ (Standard state free energy ) as

$\Delta G^o = 2 \Delta G^o _{NOCl} - \Delta G^o _{Cl_2} - 2 \Delta G^o _{NO}$

The Standard state free energy for NO is constant with a value

$\Delta G^o _{NO} = 86.55 kJ/mol$

The Standard state free energy for $Cl_2$ is constant with a value

$\Delta G^o _{Cl_2} = 0kJ/mol$

The Standard state free energy for $NOCl$ is constant with a value

$\Delta G^o _{NOCl} =66.1kJ/mol$

Now substituting this into the equation

$\Delta G^o = 2 * 66.1 - 0 - 2 * 87.6$

$= -43 kJ/mol$

The pressure constant is evaluated as

$Q = \frac{Pressure \ of \ product }{ Pressure \ of \ reactant }$

Substituting values

$Q = \frac{(7.7)^2 }{(9.2)^2 (9.15) } = \frac{59.29}{774.456}$

$= 0.0765$

The free energy for this reaction is evaluated as

$\Delta G = \Delta G^o + RT ln Q$

Where R is gas constant with a value of $R = 8.314 J / K \cdot mol$

T is temperature in K with a given value of $T = 25+273 = 298 K$

Substituting value

$\Delta G = -43 *10^{3} + 8.314 *298 * ln [0.0765]$

$= -43-6.36$

$\Delta G = -49.36 kJ$

4 0

3 years ago

What isotope is used for a standard for other atomic masses?

sergeinik [125]

Though the ratio of any two atom's masses was the same on either scale, it was horribly confusing, so in 1961, a compromise was reached. Instead of using either Hydrogen, or Oxygen as the standard, the isotope of Carbon with 6 protons and 6 neutrons in its nucleus (Carbon-12) was given a mass of exactly 12.

3 0

3 years ago

Which ion gives colored solutions and give reason? cu an Ti v

Anvisha [2.4K]

Answer: Complex ions.

5 0

3 years ago

WILL GIV, BRAINLISE IS URGENT PLZZZ

Assoli18 [71]

Explanation:

1: fluorine to form lithium fluoride

2:bcos covalent bond exists btw two non metals

3: bcos it is d combination of two or more elements nd elements r substances

4: for sbustances we hv flame test nd splint test

ionic compounds are held by strong electrostatic forces of attraction

7 0

3 years ago

Read 2 more answers

Which of the following describes the greenhouse effect?

forsale [732]

Answer:

Explanation:

Earth's greenhouse gases trap heat in the atmosphere and warm the planet.

5 0

3 years ago