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IgorLugansk [536]
3 years ago
6

Very few fossil of jelly fish or their close relatives have been found. This makes it hard to trace the evolutionary history of

jellyfish using fossil record. what explain this
Chemistry
2 answers:
dsp733 years ago
7 0
This statement explains that jelly fish in an endemic species 
ehidna [41]3 years ago
6 0
Jellyfish dont have bones. fossils formed from bones or rock formation.
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they are made by of two types of elementary particles

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quetion answered by

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3 years ago
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2.04 thermal and chemical change
bazaltina [42]

Explanation:

thermal changes are those in which heat exchange is involved like endothermic and exothermic

while in chemical changes collision between the reactant occurs which result into product

8 0
1 year ago
Aplica el método científico. Toma en cuenta que el desplazamiento de un vehiculo , el paso de la electricidad por los cables la
Daniel [21]

Answer:

Revisa con detalle la explicación.

Explanation:

¡Hola!

En este caso, debemos tener en cuenta que los pasos básicos del método científico son:

- Observación.

- Experimentación.

- Registro de datos.

- Análisis.

- Conclusiones

Para el primer caso (desplazamiento de un vehiculo), consideramos la primera ley de Newton o también ley de inercia en la cual explica que un cuerpo se mantendrá en reposo o en constante movimiento hasta el momento en que se aplica una fuerza externa.

Con los pasos del método científico encontramos que para el desplazamiento de un vehiculo se encuentra inicialmente en reposo pero luego se aplica una fuerza que hace que se mueva. Luego para la experimentación, se realiza un experimento con un carro de juguete (por ejemplo) inicialmente en reposo y al que se le aplica una fuerza para moverlo, con lo que se realiza el análisis y finalmente se obtiene la conclusión a la que llegó Newton.

Paso de electricidad: cuando se observa que hay algún dispositivo encendido, es posible usar un voltímetro para comprobar dicho paso por medio de mediciones.

Combustion del papel: cuando se enciende un trozo de papel con fuego y se observa que convierte en ceniza, es posible realizar el experimento con el fin de llegar a la conclusión de que al reaccionar con oxígeno, cambia la escructura de la celulosa a carbon, dióxido de carbono, agua y otros residuos.

Asimismo, al llevar a cabo experimentos de coagulación de la sangre en una herida y como los nutrientes obtenidos de los alimentos se convierten en energía para nosotros, podemos llegar a las conclusiones de que la sangre se coagula debido la existencia de plaquetas y que los alimentos se convierten en energía a partir de las enzimas que tenemos dentro de las células que los degradan en glucosa y lípidos reutilizables.

¡Saludos!

8 0
3 years ago
If a single gold atom has a diameter of 2.9×x10−8 cm, how many atoms thick was rutherford's foil
ale4655 [162]

27,586

<h3>Further explanation</h3>

<u>Given:</u>

A single gold atom has a diameter of \boxed{ \ 2.9 \times 10^{-8} \ cm. \ }

From a reference, the Rutherford gold foil used in his scattering experiment had a thickness of approximately \boxed{ \ 8 \times 10^{-3} \ mm. \ }

<u>Question:</u>

How many atoms thick were Rutherford's foil?

<u>The Process:</u>

Convert thickness from mm to cm.

\boxed{ \ 8 \times 10^{-3} \ mm = 8 \times 10^{-3} \times 10{-1} \ cm \ } \rightarrow \boxed{ \ 8 \times 10^{-4} \ cm \}

The number of atoms is calculated from gold foil thickness divided by the atomic diameter.

\boxed{ \ = \frac{8 \times 10^{-4} \ cm}{2.9 \times 10^{-8} \ cm} \ }

\boxed{ \ =2.7586 \times 10^4 \ atoms \ }

Therefore, we get an atomic thickness of 27,586 atoms.

<u>Notes:</u>

  • In 1909-1910, Ernest Rutherford with two of his assistants, namely Hans Geiger and Ernest Marsden, conducted a series of experiments to find out more about the arrangement of atoms. They fired at a very thin gold plate with high-energy alpha particles.
  • One of their observations is that a small portion of alpha particles are reflected. This greatly surprised Rutherford. The reflected alpha particle must have hit something very dense in the atom. This fact is incompatible with the atomic model proposed by J.J. Thomson where the atoms are described as homogeneous in all parts with electrons and protons evenly distributed.
  • In 1911, Rutherford was able to explain the scattering of alpha rays by proposing ideas about atomic nuclei. According to him, most of the mass and positive charge of atoms are concentrated at the center of the atom, hereinafter referred to as the nucleus.
<h3>Learn more</h3>
  1. The energy density of the stored energy  brainly.com/question/9617400
  2. The theoretical density of platinum which has the FCC crystal structure. brainly.com/question/5048216
  3. Compound microscope brainly.com/question/4000241

Keywords: if a single gold atom, has a diameter of 2.9 x 10⁻⁸ cm, how many, atoms thick, Rutherford's foil, his scattering experiment

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3 years ago
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A gram of gold has the same _____ as a kilogram of gold.
aivan3 [116]
I believe it is density but i'm not for certain try looking it up somewhere else
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3 years ago
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