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wlad13 [49]
3 years ago
6

What other signs provide evidence of chemical reactions and show that a chemical change has occurred?

Chemistry
1 answer:
Dmitry_Shevchenko [17]3 years ago
4 0
Color change
new substance formed
heat or light change
new smell
irreversible 
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Identify the type of chemical bond that forms when potassium reacts with bromine to form a salt.
Sunny_sXe [5.5K]

2K + Br2 ===> 2KBr


It's very ionic. The transfer of 2 electrons from K to Br2 is nearly as complete as it can be.

3 0
3 years ago
Which of the following represents the correct ranking in terms of increasing boiling point? A. n-butane < 1-butanol < diet
bonufazy [111]

Answer:

The answer to your question is: letter E

Explanation:

Normally, the correct order of boiling points is:

                     Alcohols > Ketones > Ether > Alkane

Then

A. n-butane < 1-butanol < diethyl ether < 2-butanone

B. n-butane < 2-butanone < diethyl ether < 1-butanol

C. 2-butanone < n-butane < diethyl ether < 1-butanol

D. n-butane < diethyl ether < 1-butanol < 2-butanone

E. n-butane < diethyl ether < 2-butanone < 1-butanol

     (- 1°C)     <    34.6°C         <  79.64°C      <  117.7°C

6 0
3 years ago
A large molecule made up of smaller molecules called amino acids
Leni [432]

Answer:

Protein

Explanation:

3 0
3 years ago
1 If it takes 67 mL of 0.15 M NaOH to neutralize 134 mL of an HCl solution, what is the concentration of the HCl? (5 points)
Neporo4naja [7]

Answer:

Q₁-  The concentration of HCl = 0.075 N = 0.075 M.

Q₂-  The concentration of KOH = 7.675 mN = 7.675 mM.

Q₃-  The concentration of H₂SO₄ = 0.2115 N = 0.105 M.

Q₄-  The equivalence point is the point at which the added titrant is chemically equivalent completely to the analyte in the sample whereas the endpoint is the point where the indicator changes its color.

Explanation:

<u><em>Q₁: </em></u>

  • As acid neutralizes the base, the no. of gram equivalent of the acid is equal to that of the base.
  • The normality of the NaOH and HCl = Their molarity.

∵ (NV)NaOH = (NV)HCl

∴ N of HCl = (NV)NaOH / (V)HCl = (0.15 N)(67 mL) / (134 mL) = 0.075 N.

∴ The concentration of HCl = 0.075 N = 0.075 M.

<em><u>Q₂:</u></em>

  • As mentioned in Q1, the no. of gram equivalent of the acid is equal to that of the base at neutralization.
  • The normality of H₂SO₄ = Molarity of H₂SO₄ x 2 = 0.050 M x 2 = 0.1 N.

∵  (NV)H₂SO₄ = (NV)KOH

∴ N of KOH = (NV)H₂SO₄ / (V)KOH = (0.1 N)(27.4 mL) / (357 mL) = 7.675 x 10⁻³ N = 7.675 mN.

∴ The concentration of KOH = 7.675 mN = 7.675 mM.

<em><u>Q₃:</u></em>

  • As mentioned in Q1 and 2, the no. of gram equivalent of the acid is equal to that of the base at neutralization.
  • The normality of NaOH = Molarity of NaOH = 0.5 N.

∵ (NV)H₂SO₄ = (NV)NaOH

∴ N of H₂SO₄ = (NV)NaOH / (V)H₂SO₄ = (0.5 N)(55 mL) / (130 mL) = 0.2115 N.

∴ The concentration of H₂SO₄ = 0.2115 N = 0.105 M.

<em><u>Q₄:</u></em>

  • The equivalence point is the point at which the added titrant is chemically equivalent completely to the analyte in the sample whereas the endpoint is the point where the indicator changes its color.
  • The equivalence point in a titration is the point at which the added titrant is chemically equivalent completely to the analyte in the sample. It comes before the end point. At the equivalence point, the millimoles of acid are chemically equivalent to the millimoles of base.
  • End point is the point where the indicator changes its color. It is the point of completion of the reaction between two solutions.
  • The effectiveness of the titration is measure by the close matching between equivalent point and the end point. pH of the indicator should match the pH at the equivalence to get the same equivalent point as the end point.
4 0
3 years ago
The compound 3-methyl-1-butanethiol, (ch3)2chch2ch2sh, is found in the defensive secretion, or \"spray,\" of striped skunks. dra
bija089 [108]

Explanation: The given compound is an organic compound because it has hydrogen and carbon atoms in it.

Skeletal structure of an organic compound is defined as a structure which is composed of the skeletal atoms that are used to define a structure.

In organic chemistry, the skeletal atoms are hydrogen and carbon. The atoms other than hydrogen and carbon are termed as heteroatoms and are shown in the structure.

The skeletal structure of 3-methyl-1-butanethiol is given in the image attached.

Here, the functional group is thiol group which has a heteroatom S.

6 0
3 years ago
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