<u>Answer:</u> The volume of concentrated hydrochloric acid required is 16.53 mL
<u>Explanation:</u>
To calculate the volume of concentrated solution, we use the equation:

where,
are the molarity and volume of the concentrated solution
are the molarity and volume of diluted solution
We are given:
Conversion factor: 1 L = 1000 mL

Putting values in above equation, we get:

Hence, the volume of concentrated hydrochloric acid required is 16.53 mL
Answer: B) Wood Shavings
Reason/Explanation:
Notice what options A, C, and D have on common. Ice, salt and sugar. Those are all dissolvable. Insoluble means un-able to dissolve. It can't dissolve. Wood shavings can't dissolve in water. They will just float. Sugar, salt and ice will all dissolve. Wood shavings won't.
-DustinBR
Answer:
B) As you move across the row, the number of electrons increases and reactivity also increases.
Explanation:
The periodic table is arranged in a way that if you go across a period, the number of protons, neutrons, and electrons in an element increases. In terms of reactivity, the most reactive elements are the ones which have a high electronegativity. The electronegativity of the elements increases as you travel to the right and upwards on the periodic table.
This problem is describing a gas mixture whose mole fraction of hexane in nitrogen is 0.58 and which is being fed to a condenser at 75 °C and 3.0 atm, obtaining a product at 3.0 atm and 20 °C, so that the removed heat from the system is required.
In this case, it is recommended to write the enthalpy for each substance as follows:

Whereas the specific heat of liquid and gaseous n-hexane are about 200 J/(mol*K) and 160 J/(mol*K) respectively, its condensation enthalpy is 31.5 kJ/mol, boiling point is 69 °C and the specific heat of gaseous nitrogen is about 29.1 J/(mol*K) according to the NIST data tables and
and
are the mole fractions in the gaseous mixture. Next, we proceed to the calculation of both heat terms as shown below:

It is seen that the heat released by the nitrogen is neglectable in comparison to n-hexanes, however, a rigorous calculation is being presented. Then, we add the previously calculated enthalpies to compute the amount of heat that is removed by the condenser:

Finally we convert this result to kJ:

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