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aniked [119]
4 years ago
14

(h) The student made observations related to the contents of the Erlenmeyer flask during the titration. Identify an observation

that could have led the student to conclude that a chemical change took place during the titration.
Chemistry
1 answer:
katen-ka-za [31]4 years ago
5 0

Answer:

Explanation:

During titration indicators are often used to identify chemical changes between reacting species.

For colorless solutions in which no noticeable changes can easily be seen, indicators are the best bet. Most titration processes involves a combination of acids and bases to an end point.

Indicators are substances whose color changes to signal the end of an acid-base reaction. Examples are methyl orange, methyl red, phenolphthalein, litmus, cresol red, cresol green, alizarin R3, bromothymol blue and congo red.

Most of these indicators have various colors when chemical changes occur.

Also, there are heat changes that accompanies most of these reactions. These are also indicators of chemical changes.

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maria [59]
It is bases on "Atomic number"

In short, Your Answer would be Option B

Hope this helps!
5 0
3 years ago
Read 2 more answers
What is the quantity of heat (in kJ) associated with cooling 185.5 g of water from 25.60°C to ice at -10.70°C?Heat Capacity of S
Cerrena [4.2K]

Taking into account the definition of calorimetry, sensible heat and latent heat,  the amount of heat required is 37.88 kJ.

<h3>Calorimetry</h3>

Calorimetry is the measurement and calculation of the amounts of heat exchanged by a body or a system.

<h3>Sensible heat</h3>

Sensible heat is defined as the amount of heat that a body absorbs or releases without any changes in its physical state (phase change).

<h3>Latent heat</h3>

Latent heat is defined as the energy required by a quantity of substance to change state.

When this change consists of changing from a solid to a liquid phase, it is called heat of fusion and when the change occurs from a liquid to a gaseous state, it is called heat of vaporization.

  • <u><em>25.60 °C to 0 °C</em></u>

First of all, you should know that the freezing point of water is 0°C. That is, at 0°C, water freezes and turns into ice.

So, you must lower the temperature from 25.60°C (in liquid state) to 0°C, in order to supply heat without changing state (sensible heat).

The amount of heat a body receives or transmits is determined by:

Q = c× m× ΔT

where Q is the heat exchanged by a body of mass m, made up of a specific heat substance c and where ΔT is the temperature variation.

In this case, you know:

  • c= Heat Capacity of Liquid= 4.184 \frac{J}{gC}
  • m= 185.5 g
  • ΔT= Tfinal - Tinitial= 0 °C - 25.60 °C= - 25.6 °C

Replacing:

Q1= 4.184 \frac{J}{gC}× 185.5 g× (- 25.6 °C)

Solving:

<u><em>Q1= -19,868.98 J</em></u>

  • <u><em>Change of state</em></u>

The heat Q that is necessary to provide for a mass m of a certain substance to change phase is equal to

Q = m×L

where L is called the latent heat of the substance and depends on the type of phase change.

In this case, you know:

n= 185.5 grams× \frac{1mol}{18 grams}= 10.30 moles, where 18 \frac{g}{mol} is the molar mass of water, that is, the amount of mass that a substance contains in one mole.

ΔHfus= 6.01 \frac{kJ}{mol}

Replacing:

Q2= 10.30 moles×6.01 \frac{kJ}{mol}

Solving:

<u><em>Q2=61.903 kJ= 61,903 J</em></u>

  • <u><em>0 °C to -10.70 °C</em></u>

Similar to sensible heat previously calculated, you know:

  • c = Heat Capacity of Solid = 2.092 \frac{J}{gC}
  • m= 185.5 g
  • ΔT= Tfinal - Tinitial= -10.70 °C - 0 °C= -10.70 °C

Replacing:

Q3= 2.092 \frac{J}{gC} × 185.5 g× (-10.70) °C

Solving:

<u><em>Q3= -4,152.3062 J</em></u>

<h3>Total heat required</h3>

The total heat required is calculated as:  

Total heat required= Q1 + Q2 +Q3

Total heat required=-19,868.98 J + 61,903 J -4,152.3062 J

<u><em>Total heat required= 37,881.7138 J= 37.8817138 kJ= 37.88 kJ</em></u>

In summary, the amount of heat required is 37.88 kJ.

Learn more about calorimetry:

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7 0
2 years ago
Calculate the amount of heat needed to boil 64.7 g of benzene (C6H6), beginning from a temperature of 41.9 C . Round your answer
JulsSmile [24]

Answer: The amount of heat needed is = 4.3kJ

Explanation:

Amount of heat H = M × C × ΔT

M= mass of benzene = 64.7g

C= specific heat capacity = 1.74J/gK

ΔT = T2-T1

Where T1 is initai temperature = 41.9C

T2 is the final temperature( boiling point of benzene) = 80.1C

H= 64.7×1.74×80.7

H= 4300J

H=4.3kJ

Therefore, the amount of heat needed is 4.3kJ

8 0
3 years ago
The first step of the water cycle is that water _______________ into the air.
Arada [10]

Answer:

evaporates

Explanation:

the heat from the sun causes it to evaporate

4 0
3 years ago
Plz help I’m getting timed
valkas [14]

the answer is organism

5 0
3 years ago
Read 2 more answers
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