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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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Who is more precise when measuring the same 17.0 cm book

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Answer:

yviygyigiyvyugyivyjvhjvhjbhkbhkbkubhkvykvyivyivukvukgukyirsrssea atrhcvgjvhjbhkvkhvhkbhkbk

Explanation:

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3 years ago

Juan, a biologist, notices that a particular group of hummingbirds leaves during the colder winter months and returns during the

Katena32 [7]

Answer:

C. Tag the hummingbirds with transmitters and track their movement.

Explanation:

Hypothesis refers to the conclusion of the analysis found on the grounds of certain observations. The hypothesis is further tested and verified by performing certain experiments. In the given excerpt, Juan hypothesizes that certain group of hummingbirds fly to certain locations depending upon the season. To test the hypothesis, Juan can experiment with finding and tracking the hummingbirds and the direction in which they fly. Tagging the hummingbirds with transmitters and tracking their movement would help Juan concluding about the hypothesis.

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3 years ago

Felipe drives his car at a velocity of 28 m/s. He applies the brake, which slows the vehicle down at a rate of 6.4 m/s2 and caus

stiv31 [10]

Answer:

Explanation:

Use the one-dimensional equation

$v_f=v_0+at$ where v is the final velocity, v0 is the initial velocity, a is the acceleration, and t is the time it takes to reach that final velocity. We are solving for t. Filling in the other values:

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t = 4.4 seconds

7 0

3 years ago

If you have a light bulb connected to a circuit and you increase the current, what happens to the light bulb and the power (assu

vodomira [7]

The best and most correct answer among the choices provided by your question is the second choice or letter B.

When current is increased in a light bulb, <span>the light bulb shines brighter and the power increases.</span>

I hope my answer has come to your help. Thank you for posting your question here in Brainly. We hope to answer more of your questions and inquiries soon. Have a nice day ahead!

3 0

4 years ago

Read 2 more answers

Two children, Ferdinand and Isabella, are playing with a waterhose on a sunny summer day. Isabella is holding the hose in herhan

AVprozaik [17]

Answer:

84%

Explanation:

g = Acceleration due to gravity = 9.81 m/s²

$y_0=1\ m$

x = 10 m

t = Time taken

$v_0$ = 3.5 m/s (assumed, as it is not given)

$A_0=\pi 1.5^2$

We have the equation

$y=y_0+ut+\dfrac{1}{2}gt^2\\\Rightarrow 0=y_0-\dfrac{1}{2}gt^2\\\Rightarrow t=\sqrt{\dfrac{2y_0}{g}}\\\Rightarrow t=\sqrt{\dfrac{2\times 1}{9.81}}\\\Rightarrow t=0.45152\ s$

$x=x_0+vt\\\Rightarrow 10=0+v0.45152\\\Rightarrow v=\dfrac{10}{0.45152}\\\Rightarrow v=22.14741\ m/s$

From continuity equation we have

$Av=A_0v_0\\\Rightarrow A=\dfrac{A_0v_0}{v}\\\Rightarrow A=\dfrac{\pi 1.5^2\times 3.5}{22.14741}\\\Rightarrow A=1.11706\ cm^2$

Fraction is given by

$f=\dfrac{A_0-A}{A_0}\times 100\\\Rightarrow f=\dfrac{\pi 1.5^2-1.11706}{\pi 1.5^2}\times 100\\\Rightarrow f=84.196\ \%\approx 84\ \%$

The fraction is 84%

8 0

3 years ago