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Leokris [45]
4 years ago
8

Which of the following observations is usually not evidence of a chemical change ?

Chemistry
1 answer:
Nookie1986 [14]4 years ago
5 0

Answer:

D

Explanation:

Have a nice day

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Write this number in standard notation.<br> 1.986 x 10negative exponent 6 or 1.986 x 10^6
Brums [2.3K]

Answer:

0.000001986

Explanation:

We have the number 1.986*10^{-6}. Standard notation would basically be this number without the 10^{-6} part.

To get rid of this part, we need to move the decimal point 6 places to the left (we go left because it's negative 6, indicating division).

So, when we move the decimal point 6 places to the left, the resulting number is: 0.000001986, with 5 zeros after the decimal point before a nonzero number.

Thus, the answer is 0.000001986.

7 0
3 years ago
Question 10
sveticcg [70]

False. Sarah has not achieved homeostasis.

<h3>What is homeostasis?</h3>

It is the maintenance of a relatively unchanged internal process in the body of organisms.

Since the resting heart rate for Sarah is 70 bpm, a 100 bpm is a far cry from the normal resting heart rate.

Thus, it cannot be said that Sarah has achieved homeostasis.

More on homeostasis can be found here: brainly.com/question/3888340

#SPJ1

3 0
2 years ago
The reaction CH2CH2 + H2 → CH3CH3 is an example of
Viefleur [7K]
The choices can be found elsewhere and as follows:

<span>(1) substitution
(2) esterification
(3) addition
(4) fermentation 
</span>
I believe the correct answer is option 3. The reaction CH2CH2 + H2 → CH3CH3 is an example of an addition reaction. It is a<span> </span>reaction<span> where two or more molecules combine to form a larger one. Hope this answers the question.</span>
4 0
3 years ago
Read 2 more answers
Which is the balanced version of the half-reaction below?<br> H2S → S+H+
chubhunter [2.5K]

Answer:

C. H_2S\rightarrow S+2H^++2e^-

Explanation:

Hello there!

In this case, according to the given chemical reaction, it turns out possible to realize there is one sulfur atom on each side of the chemical equation but two hydrogen atoms on the left and one on the right, which means the latter must be balanced in agreement to the law of conservation of mass.

In such a way, by setting a 2 on H⁺, the reaction will be balanced:

H_2S\rightarrow S+2H^+

Now, we count the transfer electrons for sulfur from -2 to 0 as 2e⁻ on the right, which will match with the option C.

H_2S\rightarrow S+2H^++2e^-

Regards!

7 0
3 years ago
ASAP!IF YOU PUT LINKS YOUR REPORTED!<br><br> how does sand sifting collect plastic
ANEK [815]

Answer:

Dirty sand is piled on a sheet of fine mesh stretched between two long poles, the mesh collects the mircoplastic and other materials while allowing the sand to fall through.

5 0
3 years ago
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