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enot [183]
3 years ago
5

Which of the following is a sign a chemical reaction has occurred?

Chemistry
2 answers:
tankabanditka [31]3 years ago
6 0
A solid dissolves in abolishing forms from the mixing of 2 liquids
dimulka [17.4K]3 years ago
6 0

Answer: A solid forms when two liquids are mixed.

Explanation:

A physical reaction is defined as the reaction in which a change in shape, size takes place. No new substance gets formed in these reactions.

A chemical reaction is defined as the reaction in which a change in chemical composition takes place. A new substance is formed in these reactions.

1. A solid dissolves in liquid: Only the phase of the solid changes to aqueous and no new substance is formed, thus is a physical change.

2. A solid forms when two liquids are mixed: two liquids can forma  solid only on chemical combination and formation of new substance.

3. A solid melts to a liquid when it is heated: Only the phase of the solid changes to liquid, no new substance is formed, thus is a physical change.

4. A solid metal changes shape: Only the shape of the solid changes, thus is a physical change.

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How many atoms are in 15.0 moles of C2H6O
Burka [1]
1 mole = 6.22 x 10^23 molecules (Avogadro's number)
15 moles x (6.22 x 10^23) = 9.33 x 10^24 atoms
3 0
3 years ago
Read 2 more answers
Summarize the relationship between an electron's energy level and its location in an atom
FromTheMoon [43]

Answer:

The further an electron is from the nucleus. the greater its energy level.

Explanation:

When an electron is close to the nucleus, it is at as low an energy level as it can get.

We must put energy into an electron to pull it away from the attraction of a nucleus.

So, electrons that are further from the nucleus are at higher energy levels.

6 0
3 years ago
Student A performed gravimetric analysis for sulfate in her unknown using the same procedures we did . Results of her three tria
soldi70 [24.7K]

Answer:

The answer is Sodium Sulfate = Na2SO4  

Explanation:

Molar mass of sulfate = 1 (S) + 4 (O) = 1 (32) + 4 (16) = 32 + 64 = 96  

Molar mass of sodium sulfate = 2 (23) + 96 = 46 + 96 = 142  

% of Sulfate = (96/142)*100 = 67.6%  

Percent mistake in Studen A,  

(I) % mistake = (67.6 - 68.6)/67.6 = 1.48  

(ii) % mistake = (67.6 - 66.2)/67.6 = 2.07  

(iii) % mistake = (67.6 - 67.1)/67.6 = 0.74  

For understudy B  

(I) % mistake = (67.6 - 66.7)/67.6 = 1.33  

(ii) % mistake = (67.6 - 66.6)/67.6 = 1.48  

(iii) % mistake = (67.6 - 66.5)/67.6 = 1.63  

Sutdent An is some how exact.  

Understudy B is exact however not precise.

8 0
3 years ago
Which of the following is not true about sedimentary rocks?
Klio2033 [76]
Answer:  [D]:  "They are not part of the rock cycle."  .
______________________________________________________
6 0
3 years ago
Read 2 more answers
For 2Na (s) + Cl2(g) - 2NaCI (s) ,how many grams of sodium Chloride will be made from 115 g of sodium metal when reacted with ex
Solnce55 [7]

<u>Given:</u>

Mass of Na = 115 g

Excess Cl2

<u>To determine:</u>

Mass of NaCl produced

<u>Explanation:</u>

Given reaction is-

2Na(s) + Cl2(g) → 2NaCl(s)

Since Cl2 is in excess, Na will be the limiting reagent

As per the reaction stoichiometry Na:NaCl = 1:1

i.e. moles of Na reacted = moles of NaCl formed

Now, # moles of Na = mass of Na/atomic mass

                                  = 115 g/23 g.mol-1 = 5 moles

Therefore, moles of NaCl = 5

Molar mass of NaCl = 58 g/mol

Mass of NaCl = 5 moles * 58 g.mol-1 = 290 g

Ans: Amount of Nacl produced = 290 g

5 0
3 years ago
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