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Arturiano [62]
3 years ago
5

In the soap testing experiment, what is the purpose of adding some MgCl2 to the soap solution at the end?

Chemistry
1 answer:
lakkis [162]3 years ago
4 0

Explanation:

The water is hard due to the presence of ions of Mg²⁺. Now in hard water soaps are ineffective . Since in hard water Mg²⁺ ion forms precipitate , which concludes less number of soap molecules are present in the solution and less amount of  froth  which disables the cleansing property of the soap .

Now the experiment , the very last step is the hard water test where some amount of MgCl₂ is added ,

Now this magnesium salt act as a source of Mg²⁺ ion and now the soap action can be determined , whether it is able to form froth or not .

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Which of the following are acids by the Bronsted-Lowry Definition:
olga55 [171]

ANSWER IS (A)

EXPLANATION:

Bronsted-Lowry concept states that a substance is an acid if it can act as a H+ donor.

HCl in aqueous solution means that HCl is present in water, HCl + H2O --> H3O+ + Cl-.  This reaction will take place, the H+ from HCl will be donated to H2O. So, HCl is a bronsted-lowry acid by definition.


However, Methanol (CH3OH) its written that it is liquid, i.e. pure methanol, CH3OH(l).  It is both acidic as well as basic. when it is mixed with water then it behaves as an acid.

The last one ammonia in gas phase is also neutral because its not in water. if mixed in water it behaves as a base.



6 0
3 years ago
During an endothermic phase change, what happens to the potential energy and the kinetic energy?
antiseptic1488 [7]

During endothermic phase change, the potential energy of the system always increases while the kinetic energy of the system remains constant. The potential energy of the reaction increases because energy is been added to the system from the external environment.

<u>Explanation</u>:

  • Those are three distinct methods for demonstrating a specific energy condition of an object. They don't affect one another.
  • "Potential Energy" is a relative term showing a release of possible energy to the environment. If we accept its pattern as the overall energy state of a compound, at that point, an endothermic phase change would infer an increase in "potential" as energy is being added to the compound by the system.
  • A phase change will display an increase in the kinetic energy at whatever point the compound is transforming from a high density to a low dense phase. The kinetic energy will decrease at whatever point the compound is transforming from a less dense to high dense phase.
4 0
2 years ago
Read 2 more answers
How many moles of potassium nitrate, KNO3 are present in a sample with a mass of 85.2 g?
Bingel [31]
0.843 moles would be the answer
5 0
3 years ago
A(n) _______ is an organic compound in which a carbonyl group is bonded to a nitrogen atom. (2 points)
sineoko [7]
A(n )amide is an organic compound in which a carbonyl group is bonded to a nitrogen atom. This is <span>usually regarded as derivatives of carboxylic acids in which the hydroxyl group has been replaced by an amine or ammonia.</span>
3 0
3 years ago
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Part 1: Name the type of chemical reaction that occurs when calcium hydroxide (Ca(OH)2) reacts with nitric acid (HNO3).
liberstina [14]

<u>Answer:</u>

<u>For 1:</u> Neutralization reaction

<u>For 2: </u>Zinc is more reactive than lead and less reactive than calcium.

<u>Explanation:</u>

  • <u>For (1):</u>

When a base reacts with an acid to form a salt and water molecule, it is known as a neutralization reaction. The general equation follows:

HX+BOH\rightarrow BX+H_2O

The chemical equation for the reaction of calcium hydroxide and nitric acid follows:

Ca(OH)_2(aq)+2HNO_3(aq)\rightarrow Ca(NO_3)_2(aq)+2H_2O(l)

  • <u>For (2):</u>

A single displacement reaction is defined as the reaction in which a more reactive metal displaces a less reactive metal from its salt solution. The general chemical equation follows:

A+BX\rightarrow AX+B

where,

Metal A is more reactive than metal B

The reactivity of metals is judged by the reactivity series where a metal lying above in the series is more reactive than the metal lying below it.

From the reactivity series below,

Zinc lies above in the series than lead thus is more reactive and will easily replace lead from its aqueous solution.

While zinc lies below in the series than calcium thus is less reactive and will not easily replace calcium from its aqueous solution.

Zn(s)+Pb(NO_3)_2(aq)\rightarrow Zn(NO_3)_2(aq)+Pb(s)

Zn(s)+CaCl_2(aq)\rightarrow \text{No reaction}

5 0
3 years ago
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