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2 years ago

Properties can be observed only when the substance in a sample of matter are changing into different substance

1 answer:

8 0

The complete statement is "chemical properties can be observed only when the substance in a sample of matter are changing into different substance".

It states a key concept in chemistry.

A chemical property is the ability of a substance, element or compound, to <em>transform</em> into other substances either <em>by decomposing or by combining</em> with one or more substances.

This transformation is defined as chemical reaction.

During chemical reactions some chemical bonds are broken and others are formed leading to the formation of one or more different substances called products.

Some examples of chemical properties are: reactivity with oxygen, reactivity with water, acidity, basicity, oxidation, reduction. The only way to tell if a substance has certain chemical property is by letting it react and so observe the change of the original substance into one or more different substances.

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Need help ASAP

VARVARA [1.3K]

Answer:

the correct one is D,

Ultraviolet, x-ray, gamma ray

Explanation:

Electromagnetism radiation are waves of energy that is expressed by the Planck relationship

E = h f

where h is the plank constant and f the frequency of the radiation.

Also the speed of light is

c = λ f

we substitute

E = h c /λ

therefore to damage the cells of the body radiation of appreciable energy is needed

microwave radiation has an energy of 10⁻⁵ eV

infrared radiation E = 10⁻² eV

visible radiation E = 1 to 3 eV

radiation Uv E = 3 to 6 eV

X-ray E = 10 eV

gamma rays E = 10 5 eV

therefore we see that the high energy radiation is gamma rays, x-rays and ultraviolet light.

When checking the answers, the correct one is D

6 0

2 years ago

Which of the following examples illustrates static friction in action?

lilavasa [31]

I think its d. but im not sure

3 0

2 years ago

Read 2 more answers

Um aluno pretende construir um aquecedor usando um enrolamento de fio. Experimenta e verifica que não

Vlad1618 [11]

Answer:

dddjebdhdjwopdjhgvvdr

6 0

2 years ago

Jumping up before the elevator hits. After the cable snaps and the safety system fails, an elevator cab free-falls from a height

noname [10]

Answer:

a) I = 2279.5 N s , b) F = 3.80 10⁵ N, c) I = 3125.5 N s and d) F = 5.21 10⁵ N

Explanation:

The impulse is equal to the variation in the amount of movement.

I =∫ F dt = Δp

I = m $v_{f}$ - m v₀

Let's calculate the final speed using kinematics, as the cable breaks the initial speed is zero

$v_{f}$ ² = V₀² - 2g y

$v_{f}$ ² = 0 - 2 9.8 30.0

$v_{f}$ = √588

$v_{f}$ = 24.25 m/s

a) We calculate the impulse

I = 94 24.25 - 0

I = 2279.5 N s

b) Let's join the other expression of the impulse to calculate the average force

I = F t

F = I / t

F = 2279.5 / 6 10⁻³

F = 3.80 10⁵ N

just before the crash the passenger jumps up with v = 8 m / s, let's take the moments of interest just when the elevator arrives with a speed of 24.25m/s down and as an end point the jump up to vf = 8 m / n

c) I = m $v_{f}$ - m v₀

I = 94 8 - 94 (-24.25)

I = 3125.5 N s

d) F = I / t

F = 3125.5 / 6 10⁻³

F = 5.21 10⁵ N

7 0

2 years ago

Why do elements need to be heated to emit color?

kirill115 [55]

Light carries away the energy. At a room temperature they are at their lowest energy

7 0

2 years ago