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Diano4ka-milaya [45]
3 years ago
9

Which of the following is NOT evidence that a chemical reaction has occurred?

Chemistry
1 answer:
sasho [114]3 years ago
3 0

It depends whats the options

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When heated solid silver oxide decomposes into its elements
ollegr [7]
Hi!

When Silver Oxide (Ag20) is heated, it decomposes into Silver and Oxygen.
5 0
3 years ago
Ethylene oxide (EO) is prepared by the vapor-phase oxidation of ethylene. Its main uses are in the preparation of the antifreeze
Rashid [163]

Answer:

a. ΔH^0_{rxn} = -108.0\frac{kJ}{mol}

b. 320.76° C

Explanation:

a.)

we can solve this type of question (i.e calculate ΔH^0_{rxn} , for the gas-phase reaction )  using the Hess's Law.

ΔH^0_{rxn} =  E_{product} deltaH^0_{t}-E_{reactant} deltaH^0_{t}

Given from the question, the table below shows the corresponding  ΔH^0_{t}(kJ/mol) for each compound.

Compound                    H^0_{t}(kJ/mol)

Liquid EO                       -77.4

CH_4_(g_)                            -74.9                

CO_(g_)                              -110.5

If we incorporate our data into the above previous equation; we have:

ΔH^0_{rxn} = (-110.5 kJ/mol + (-74.9 kJ/mol) ) - (-77.4 kJ/mol)

          =   -108.0 \frac{kJ}{mol}

b.)

We are to find the final temperature if the average specific heat capacity of the products is 2.5 J/g°C

Given that:

the specific heat capacity (c) = 2.5 J/g°C

T_{initial} = 93.0°C   &

the  enthalpy of vaporization  (ΔH^0_{vap}) = 569.4 J/g

If, we recall; we will remember that; Specific Heat Capacity is the amount of heat needed to raise the temperature of one gram of a substance by one kelvin.

∴ the specific heat capacity (c) is given as =  \frac{Heat(q)}{mass*changeintemperature(T_{initial}-T_{final})}

Let's not forget as well, that  ΔH^0_{vap} = \frac{q}{mass}

If we substitute  ΔH^0_{vap}  for  \frac{q}{mass} in the above equation, we have;

specific heat capacity (c) = \frac{deltaH^0_{vap}}{T_{final}-T_{initial}}

Making (T_{final}- T_{initial}) the subject of the formula; we have:

T_{final}- T_{initial}  = \frac{delat H^0_{vap}}{specificheat capacity}

(T_{final}-93.0^0C)=\frac{569.4J/g}{2.5J/g^0C}

T_{final}=\frac{569.4J/g}{2.5J/g^0C}+93.0^0C

         = 227.76°C +93.0°C

          = 320.76°C

∴ we can thereby conclude that the final temperature = 320.76°C                

7 0
3 years ago
What does resonance result in?
Tcecarenko [31]

louder sounds

Explanation:

Resonance results in louder sounds.

Resonance is a phenomenon that produces a large vibration as a result of smaller vibration that causes the resonating body to vibrate at its own natural frequency.

Resonance results in sound amplification and causes louder sounds. Increasing vibration results in the production of a louder sound.

Learn more:

Resonance in chemistry brainly.com/question/9422880

#learnwithBrainly

3 0
3 years ago
Erosion and weathering can both cause changes to the surface of Earth. Which of the following happens only because of erosion an
dangina [55]

Answer:

caves

Explanation:

BRAINLIEST

You didn't give any examples

7 0
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What factors affect the difference in the color of the stars
MAVERICK [17]

Answer:

My answer is Temperature

3 0
3 years ago
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