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Georgia [21]
3 years ago
7

PLEASEEEEEEEEEEE HELP WILL MARK BRAINLIEST!!!!!!!!!!!

Chemistry
2 answers:
slamgirl [31]3 years ago
7 0

Answer:

The correct statement is that Example A describes a chemical change and Example B describes a physical change.

Explanation:

  1. In example A we have a chemical change because the use of soaps and detergents implies a chemical reaction called saponification due to the soap molecules has a double component the first part of a soap is called hydrophilic and the second part is called hydrophobic. so, when the soap molecules interact with the oil molecules in water the hydrophilic part will be bonded with water and the hydrophobic part will be bonded with the oil. This new bondings are called micelles and the formations of micelles by new bonds it is a chemical change.
  2. In example B there is a physical change because the water in a Bowl is evaporated. it means that at higher temperatures the molecules of water pass from the liquid state of the matter to the gas state. This physical change happens after the water molecules reach enough energy able to broke surface tension in liquid water. This energy is obtained thanks to the increasing of temperature, and the temperature needed to achieve this change from liquid to gas is called boiling point.

Sidana [21]3 years ago
3 0
Example A describes a chemical change and Example B describes a physical change.
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Nitric acid can be produced by the reaction of gaseous nitrogen dioxide with water. 3 no2(g + h2o(? ?? 2 hno3(? + no(g if 538 l
Phantasy [73]
The balanced chemical reaction is written as:

<span>3NO2 + H2O = 2HNO3 + NO

Assuming that the gases in this reaction are ideal gas, then we can use the conversion from L to moles which is 1 mol of ideal gas is equal to 22.4 L. We calculate as follows:

538 L NO2 ( 1 mol / 22.4L ) ( 1 mol NO / 3 mol NO2 ) ( 22.4 L / 1 mol ) = 179.33 L NO is produced</span>
8 0
3 years ago
Calculate the pH in titration of a weak acid: What is the pH in titration of formic acid (HCHO2, 0.200 M, 100.0 mL) after the ad
ki77a [65]

Answer:

pH = 12.61

Explanation:

First of all, we determine, the milimoles of base:

0.120 M = mmoles / 300 mL

mmoles = 300 mL . 0120 M = 36 mmoles

Now, we determine the milimoles of acid:

0.200 M = mmoles / 100 mL

mmoles = 100 mL . 0.200M = 20 mmoles

This is the neutralization:

HCOOH    +     OH⁻         ⇄        HCOO⁻     +    H₂O

20 mmol       36 mmol             20 mmol

                    16 mmol

We have an excess of OH⁻, the ones from the NaOH and the ones that formed the salt NaHCOO, because this salt has this hydrolisis:

NaHCOO  →  Na⁺  +  HCOO⁻

HCOO⁻  +  H₂O  ⇄   HCOOH  +  OH⁻   Kb →  Kw / Ka = 5.55×10⁻¹¹

These contribution of OH⁻ to the solution is insignificant because the Kb is very small

So:  [OH⁻] =  16 mmol / 400 mL →  0.04 M

- log  [OH⁻]  = pOH →  1.39

pH = 14 - pOH → 12.61

6 0
3 years ago
20 points to whoever can answer these 3 questions correctly
vazorg [7]

Answer:

1.true

2.2

3. false

Explanation:

.........

5 0
2 years ago
PLEASE HELP!!
tensa zangetsu [6.8K]

Answer:

5

Explanation:

6 0
3 years ago
............................
I am Lyosha [343]

I think the answer is A or C sorry for not having that good of an answer

5 0
3 years ago
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