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2 years ago

Which method of testing substances is a sure way to identify a chemical reaction?

2 answers:

8 0

Chemical reaction includes chemical changes (modifications in the structures of molecules, new compounds )of the substances in the reaction. As a result of the chemical reaction new substances are formed that cannot be reversed using physical means.

The following method of testing substances is a sure way to identify a chemical reaction:

A. color change

B. Formation of bubbles

D. increase in temperature

Dmitrij [34]2 years ago

3 0

A change in color hope it helps

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Einstein calculated that ripples of gravity travel at exactly the speed of _____

damaskus [11]

Answer:

299,792,458 m/s = speed of light

Explanation:

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2 years ago

A boy throws a stone straight upward with an initial speed of 15m/s. What maximum height will the stone reach before falling bac

Vitek1552 [10]

$height=\frac{velocity^2}{2gravity}\\\\
velocity=15\frac{m}{s}\\\\
g=9,8\frac{m}{s^2}\\\\height=\frac{15^2}{2*9,8}=\frac{225}{19,6}\\\\
\boxed{height=11,48\ meters}$

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2 years ago

A falling skydiver has a mass of 105 kg. What is the magnitude of the skydiver's acceleration when the upward force of air resis

LenKa [72]

F-free = m*g - F_air = m*a

F_air = 1.2 * m

a= (105 kg * 9.8 m.s^2 - 5*105) / 105 kg

a = 9.3 m/s

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7 0

2 years ago

10 turns of wire are closely wound around a pencil as shown in the figure. when measured using a scale as shown, the length of t

Mila [183]

Answer:

a. The thickness of the wire is 2.5 mm.

b. The wire is 0.25 cm thick.

Explanation:

Number of turns of the wire = 10

The length of total turns = 25 mm

a. The thickness of the wire can be determined by;

thickness of the wire = $\frac{length of total turns}{number of turns}$

= $\frac{25}{10}$

= 2.5 mm

Therefore, the wire is 2.5 mm thick.

b. To determine the thickness of the wire in centimetre;

10 mm = 1 cm

So that,

2.5 mm = x

x = $\frac{2.5}{10}$

= 0.25 cm

The wire is 0.25 cm thick.

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2 years ago

Why do we see black? Is light being admitted reflected or absorbed or transmitted

Diano4ka-milaya [45]

Answer:When white light strikes an object, each individual frequency of light is transmitted, reflected, or absorbed, depending on the properties of the surface molecules. If all frequencies are absorbed by the object, then it appears black. If all frequencies are reflected, then it appears white.

Explanation:

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2 years ago