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denis23 [38]
3 years ago
10

Which of the following is an example of qualitative observation?Select one of the options below as your answer:. A. Joseph is ob

serving the color difference in the reaction mixture of each of the test samples to see what types of proteins are present in them.. B. Joseph is measuring the color of the reaction mixture colorimetrically to see the concentration of proteins in the sample.. C. Joseph is observing the color of the reaction mixture to see whether proteins are present in the given solution..
Chemistry
2 answers:
masya89 [10]3 years ago
8 0
The probable answer here is letter C. 
Letter A can't be the answer since when we talk about color differences there is a "difference involve. So it is observing the magnitude of the change in color. 
Letter B can't be the answer since when we involve colorimetry, there is a corresponding values to these readings. This is actually a quantitative test. 
Letter C is the answer since, we are just observing if there is a certain color appears after the reaction takes place. 
vekshin13 years ago
5 0
<h2>Answer : Option C) Joseph is observing the color of the reaction mixture to see whether proteins are present in the given solution.</h2><h3>Explanation :</h3>

An example of qualitative observation is the one where one uses the five senses to identify the changes in the reaction.

Here, when Joseph is studying a reaction mixture he is trying to observe a color change which will confirm that there is proteins present in the reaction mixture or not If there is a color change observed then it will confirm the presence of proteins.

Usually qualitative observations are those which can be easily predicted by using five senses.


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The enthalpy of vaporization of liquid water at 100°C is 2257 kJ/kg. Determine the enthalpy for apordato of iuod eeat capacity o
igomit [66]

Explanation:

The given data is as follows.

         T_{1} = 100^{o}C,       T_{2} = 10^{o}C

       \Delta H_{vap1} = 2257 kJ/kg,     \Delta H_{vap2} = ?

For water, C_{p} = 4.184 kJ/kg ^{o}C

Formula to calculate heat of vaporization is as follows.

  \Delta H_{vap1} - \Delta H_{vap2} = C_{p}(T_{1} - T_{2})

Hence, putting the values into the above formula as follows.

\Delta H_{vap1} - \Delta H_{vap2} = C_{p}(T_{1} - T_{2})

2257 kJ/kg - \Delta H_{vap2} = 4.184 kJ/kg ^{o}C (100 - 10)^{o}C

            \Delta H_{vap2} = 2257 kJ/kg - 376.56 kJ/kg

                                       = 1880.44 kJ/kg

Thus, we can conclude that enthalpy of liquid water at 10^{o}C is 1880.44 kJ/kg.

3 0
2 years ago
If 4.9 kg of CO2 are produced during a combustion reaction, how many molecules of CO2 would be produced?
solmaris [256]

Answer:

6.7 x 10²⁶molecules

Explanation:

Given parameters

Mass of CO₂  = 4.9kg  = 4900g

Unknown:

Number of molecules  = ?

Solution:

To find the number of molecules, we need to find the number of moles first.

 Number of moles  = \frac{mass}{molar mass}

          Molar mass of CO₂  = 12 + 2(16)  = 44g/mol

   Number of moles  = \frac{4900}{44}  = 111.36mole

A mole of substance is the quantity of substance that contains the avogadro's number of particles.

       1 mole  = 6.02 x 10²³molecules

     111.36 moles  =   111.36 x 6.02 x 10²³molecules   = 6.7 x 10²⁶molecules

5 0
3 years ago
Am I incorrect ?<br> Or nah?
Mademuasel [1]
I think so... I'm currently learning this too but you should be correct
4 0
3 years ago
Read 2 more answers
Hess’s law
Delvig [45]

From the statement of Hess' law, the enthalpy of the reaction A---> C is +90 kJ

<h3>What is Hess' law?</h3>

Hess' law of constant heat summation states that for a multistep reaction, the standard enthalpy of reaction is always constant and is independent of the pathway or intermediate routes taken.

From Hess' law, the enthalpy change for the reaction A ----> C is calculated as follows:

A---> C = A ---> B + B ---> C

ΔH of A---> C = 30 kJ + 60 kJ

ΔH = 90 kJ

Therefore, the enthalpy of the reaction A---> C is +90 kJ

The above reaction A---> C can be shown in the enthalpy diagram below:

A -------------------> C (ΔH = +90 kJ)

\ /

\ / (ΔH = +60 kJ)

(ΔH = +30 J) \ /

> B

Learn more about enthalpy and Hess law at: brainly.com/question/9328637

8 0
2 years ago
Scientists use what properties to help them identify and classify matter
Volgvan
Scientists use the physical and chemical properties to help them identify and classify matter. These physical and chemical properties are in a macro-perspective, in which these matter contains compounds, elements and atoms. Hence, matter can be classified in various ways, <span><span>
1.    </span>Atomic number either atomic mass each element has</span> 
<span><span>2.    </span>By substance of that matter either pure substance or mixed substance</span> <span>
3.    If they cannot reduce a certain substance into a much smaller quantified atomic structure then they they’ll use (2) to identify and classify it.</span>
5 0
3 years ago
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