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3 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]3 years ago

3 0

A change in color hope it helps

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A coin 15.0 mm in diameter is placed 15.0 cm from a spherical mirror. The coin's image is 5.0 mm in diameter and is erect. Is th

s344n2d4d5 [400]

Answer:

15 cm

Explanation:

$h_{o}$ = Diameter of the coin = 15 mm

$h_{i}$ = Diameter of the image of coin = 5 mm

$d_{o}$ = distance of the coin from mirror = 15 cm

$d_{i}$ = distance of the image of coin from mirror = ?

Using the equation

$\frac{d_{i}}{d_{o}} = \frac{- h_{i}}{h_{o}}$

$\frac{d_{i}}{15} = \frac{- (5)}{15}$

$d_{i}$ = - 5 cm

$R$ = radius of curvature

Using the mirror equation

$\frac{1}{d_{o}} + \frac{1}{d_{i}} = \frac{2}{R}$

$\frac{1}{15} + \frac{1}{- 5} = \frac{2}{R}$

$R$ = - 15 cm

6 0

3 years ago

Both physical and chemical changes are accompanied by a change in the total energy of the system, which is divided into two broa

olga2289 [7]

Answer:

I believe <u>kinetic / potential</u>

Explanation:

8 0

2 years ago

On a violin, the highest note Mandy can play is an A-note, which produces a sound wave with a high frequency. The lowest note sh

lora16 [44]

I think the answer would be: The G-note's wavelength is longer

Here are the formula to calculate wavelength

Wavelength = Wave speed/Frequency

Which indicates that the wavelength will become larger as the frequency became smaller.

6 0

3 years ago

Read 2 more answers

A drag racer starts her car from rest and accelerates at 5.5 m/s2 for the entire distance of 523 m. How long did it take the car

ANEK [815]

Answer:

t = 13.7 s or t = 14 s with proper significant figures

Explanation:

The initial speed is 0 m/s since the car starts from rest, acceleration is 5.5 m/s2 and distance is 523 m.

Since we have initial speed, acceleration and distance we can use the following formula to find the time. We can now use algebra to work out our answer.

d = vt + $\frac{1}{2}$ at²

523 = (0)t + ( $\frac{1}{2}$ )(5.5)t²

523 = 2.8t²

186.8 = t²

13.7 s = t

(t = 14 s with proper significant figures)

3 0

2 years ago

On Earth, plasma exists in the ionosphere, in flames, and in chemical and nuclearexplosions. Matter in a controlled thermonuclea

nasty-shy [4]

The cost of developing thermonuclear power with plasmabe defended because D. It can provide an inexpensive power source.

<h3>How did the cost of developing thermonuclear power defended?</h3>

The cost of developing thermonuclear power defended becvause we can see in the paragraph how it was told that the generation of ths power can be donee through the understanding of the occurrence of plasmain nature,

It should be noted that this thermonuclear power with plasmabe posses the characteristics which make it to exist in the ionosphere, and it can be felt in the flames as well; as in the chemical and nuclearexplosions.

In conclusion the power can be seen as an inexpensive source power because the p[roduction of this power cn be found in most of the thing that can be found around us as discused above.

Therefore, option D is correct.