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3 years ago

Which of these is an indication that a chemical reaction has occurred?

Chemistry

2 answers:

kirill [66]3 years ago

8 0

C. Formation of a precipitate.

Kobotan [32]3 years ago

7 0

Answer:

The correct option is C.
Formation of a precipitate

Explanation:

During a chemical reaction, new substances are formed known as a products, mostly reaction occur and their product is obtained as precipitates.

Example

Arylidene-2-thiobarbituric acid is obtained as precipitates when aldehyde and thiobarbituric acid react to each other.

melting of a substance

It is just indication of physical changes, like melting of ice, composition remained same as before.

boiling of a substance

It is just indication of physical changes, like boiling of water into vapors, composition remained same as before.

freezing of a substance

It is just indication of physical changes, like freezing of water into ice, composition remained same as before

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How many grams of nacl are in 250 g of a 15.0% (by weight) solution?

Gelneren [198K]

Answer: -

37.5 g of NaCl are in 250 g of a 15.0% (by weight) solution.

Explanation: -

Total mass = 250 g

Percentage of NaCl = 15.0 %

= $\frac{Number of grams of NaCl present}{total mass}$

Thus $\frac{15}{100}$ = $\frac{Number of grams of NaCl present}{250g}$

Number of grams of NaCl present = $\frac{15 x 250g}{100}$

= 37.5 g

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4 years ago

When the nail was copper-plated in Part III of the lab, what element do you think was reduced? Explain your answer in complete s

Jet001 [13]

Reduction always results in a lowering of the oxidation number. The reaction of the system above is written as:

Cu2+(aq) + Fe(s) --> Cu(s) + Fe2+(aq)

From the reaction, we see that copper goes from the +2 to a neutral charge. Lowering of the oxidation number happens so this is the element that is being reduced.

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3 years ago

5g of aspirin will powder will take effect more quickly than a 5g aspirin tablet because the powder has more what

Pani-rosa [81]

Answer:

Explanation:

Because the powder has more finer and larger surface area hence it absorbed faster and it becomes more effective in performance compared to the tablet that will still need to be dissolved before it is been assimilated into the body system.

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4 years ago

A motorcycle that travels north 201m in 7s. What is it's velocity? 7. D= 8. TE 9. V=

timama [110]

The velocity would be 0.5 i think

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3 years ago

ANSWER AS SOON AS POSSIBLE PLEASE!!!! Which type of water represents the largest percentage of earths water?

antoniya [11.8K]

Answer:

im pretty sure its groundwater just read this and see the answer

Explanation:

The ocean holds about 97 percent of the Earth's water; the remaining three percent is found in glaciers and ice, below the ground, in rivers and lakes. Of the world's total water supply of about 332 million cubic miles of water, about 97 percent is found in the ocean.

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3 years ago

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