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Flura [38]
4 years ago
7

Which statement correctly describes a physical change?

Chemistry
2 answers:
Alja [10]4 years ago
8 0
<span>may involve a change in phase but does not involve a change in the molecular structure

involves energy transfer and change in color</span>
zloy xaker [14]4 years ago
4 0

Answer:

May involve a change in phase but does not involve a change in the molecular structure

Explanation:

A physical change is change in phase.

For example a change from liquid to solid or solid to gas etc.

If there is a change at molecular structure it means the process if chemical.

For example breaking of hydrogen molecule to monoatomic hydrogen.

If there is a change involving conversion of one substance to other or generation of new substances then it must be a chemical change.

For example combination of hydrogen with oxygen to form water molecule.

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Which of the following types of electromagnetic waves generally has the least energy
sertanlavr [38]

Radio waves have the lowest energy, but the longest wavelength. So radio waves is the answer. Good luck on the rest and message me for more help.

7 0
3 years ago
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All bodies of water make up a earth's
Delvig [45]

Hey there!

The answer is C, hydrosphere.

The prefix "hydro" means water.

"Sphere" relates to Earth.

The asthenosphere and lithosphere are parts of the crust and mantle of the earth.

The atmosphere is the gases that surround the planet.

Hope this helps!

3 0
4 years ago
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A liquid has a<br> volume and a<br> sha<br> shape.<br> fixed<br> variable
serious [3.7K]

Answer: No definite shape.

Explanation:A liquid is a state of matter. A liquid is in close contact with each other ,therefore liquid has a definite volume but due to the close contact with each other, it has no shape rather it takes the shape of the container.

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4 years ago
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5. CaCO, - CaO+CO,<br> Reaction Type
ruslelena [56]

Answer:

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3 0
3 years ago
The rate constant of a certain reaction is known to obey the Arrhenius equation, and to have an activation energy Ea = 71.0kJ/mo
aleksandrvk [35]

Explanation:

Relation between temperature and activation energy according to Arrhenius equation is as follows.

            k = A exp^{\frac{-E_{a}}{RT}}

where,   k = rate constant

              A = pre-exponential factor

           E_{a} = activation energy

             R = gas constant

              T = temperature in kelvin

Also,  

         ln (\frac{k_{2}}{k_{1}}) = (\frac{-E_{a}}{R}) \times (\frac{1}{T_{2}} - \frac{1}{T_{2}})

      T_{1} = 244^{o}C = (244 + 273) K = 517.15 K

      T_{2} = 324^{o}C = (597.15 + 273) K = 597.15 K

     k_{1} = 6.7 M^{-1} s^{-1},     k_{2} = ?

         R = 8.314 J/mol K

      E_{a} = 71.0 kJ/mol = 71000 J/mol

Putting the given values into the above formula as follows.

   ln (\frac{k_{2}}{6.7}) = (\frac{-71000}{8.314} \times (\frac{1}{597.15} - \frac{1}{517.15})

                   = 2.2123

        \frac{k_{2}}{6.7} = exp(2.2123)

                    = 9.1364

                k_{2} = 61 M^{-1}s^{-1}

Thus, we can conclude that rate constant of this reaction is 61 M^{-1}s^{-1}.

3 0
4 years ago
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