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3 years ago

Min : sec helium and nickel are classified as _____, which are pure substances that make up all kinds of matter

1 answer:

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Helium which has a chemical formula of He is considered as a noble gas while Nickel which has a chemical formula of Ni is considered as metallic. Although both have different phases but they are both classified under the general category of “Elements”.

answer:

elements

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What is the binding energy of a nucleus that has a mass defect of 5.81*10-^29 kg

IrinaVladis [17]

Answer:

Choice A: Approximately $5.23 \times 10^{-29}$ joules.

Explanation:

Apply the famous mass-energy equivalence equation to find the energy that correspond to the $\rm 5.81\times 10^{-29}$ kilograms of mass.

$E = m \cdot c^{2}$ ,

where

$E$ stands for energy,
$m$ stands for mass, and
$c$ is the speed of light in vacuum.

The speed of light in vacuum is a constant. However, finding the right units for this value can simplify the calculations a lot. What should be the unit of $c$ ?

The mass given is in the appropriate SI unit:

Mass is in kilograms.

Thus, proceed with the speed of light in SI units. The SI unit for speed is meters per second. For the speed of light, $c \approx \rm 3.00\times 10^{8}\;m\cdot s^{-1}$ .

Apply the mass-energy equivalence:

$\begin{aligned} E &= m \cdot c^{2} \\ &= \rm 5.81\times 10^{-29}\; kg \times {\left(3.00\times 10^{8}\; m\cdot s^{-1}\right)}^{2}\\ &\approx \rm 5.23\times 10^{-12}\;kg\cdot m^{2}\cdot s^{-2} \end{aligned}$ .

The unit of energy is not in joules. Don't be alerted. Consider the definition of a joule of energy. One joule is the work done on an object when a force of one newton acts on the object in the direction of the force through the distance of one meter. (English Wikipedia.)

$\rm 1\; J = 1\; N \times 1\; m$ .

However, a force of one newton is defined as the force required to accelerated an object with a mass of one kilogram (not gram) at a rate of one meter per second squared. (English Wikipedia.)

$\begin{aligned}\rm 1\; J &= \rm 1\; N \times 1\; m\\ & = \rm \left(1\; kg\times 1\; m\cdot s^{-2}\right)\times 1\; m\\ &= \rm 1\; kg \cdot m^{2}\cdot s^{-2}\end{aligned}$ .

In other words, the mass defect here is also $\rm 5.23\times 10^{-12}\; J$ .

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3 years ago

Read 2 more answers

Which is an indicator of poor air quality? salt bacteria fertilizer smog

nlexa [21]

Smog

formed by mixture of smoke and fog

3 0

4 years ago

A is scientific knowledge established through direct observation and remains constant. Scientific knowledge can change when scie

tatyana61 [14]

This is a fill in the blanks question.

This is where the blanks are: A __________ is scientific knowledge established through direct observation and remains constant. Scientific knowledge can change when scientists _____________

The answer is followiing.

Answer: A law is scientific knowledge established through direct observation and remains constant. Scientific knowledge can change when scientists find new evidence.

Explanation:

A scientific law describes the relation (usually in mathematical terms) of natural phenomena and is supported by numerous observations and experiments. The laws are established when all the observations and result show that all the facts obey the same relation. For instance, the Universal law of gravitation: all the objects are attracted with a force that is directly proportional to the product of their masses and inversely related to the square of the distance that separates them: in lay terms, everything that goes up has to go down, and you do not expect that when a parachutist jumps out of an airplane he or she does not fall on the ground.

On the other hand, a scientific theory, although is an explanation that has been repeatedly tested and verified, is always under scientific scrtutiny and, as additional evidence is gathered it can be modified or replaced by a new theory. That is why it is said that scientific theories have to be testable and falsiable: if it is not testable and falsiable then it is not a scientific theory.

Scientific theories are aimed to describe, explain and make predictions about the objectivable world.

6 0

3 years ago

Write a chemical equation showing how this is an acid according to the Arrhenius definition. Express your answer as a balanced c

mylen [45]

Answer:

$HC_2H_3O_2_{(aq)}\rightarrow H^+_{(aq)}+C_2H_3O_2^-_{(aq)}$

Explanation:

Arrhenius theory:-

The Arrhenius theory was introduced introduced by Swedish scientist named Svante Arrhenius in 1887.

According to the theory, acids are the substances which dissociate in the aqueous medium to produce electrically charged atoms ( may be molecule). Out of these species furnished, one must be a proton or the hydrogen ion, $H^+$ .

So,

The expression for acid, $HC_2H_3O_2$ is:-

$HC_2H_3O_2_{(aq)}\rightarrow H^+_{(aq)}+C_2H_3O_2^-_{(aq)}$

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3 years ago

What role could energy have played in forming the black sand on the beach?

Ivan

The role energy would have played in forming the black sand on the beach

will be through the erosion and movement of the particles.

Black sand from the beach are formed as a result of the erosion of volcanic

material , dark-colored rocks and minerals. Erosion helps to carry these

particles to the beach thereby making the color of the sand to become dark.

The wave energy present at the beach erodes and moves the materials to

different parts of the beach.

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3 years ago