Answer:
The mass of 0.280 mole sample of sodium hydroxide NaOH is 11.2 grams.
Explanation:
To know the mass in grams of 0.280 moles of sample of sodium hydroxide NaOH, you must know the molar mass of the compound, that is, the mass of one mole of a substance, which can be an element or a compound.
So you know:
- Na: 23 g/mole
- O: 16 g/mole
- H: 1 g/mole
So, the molar mass of NaOH is:
NaOH= 23 g/mole + 16 g/mole+ 1 g/mole= 40 g/mole
Then the following rule of three can be applied: if in 1 mole of sodium hydroxide there are 40 grams, in 0.280 moles how much mass is there?

mass= 11.2 grams
<u><em>The mass of 0.280 mole sample of sodium hydroxide NaOH is 11.2 grams.</em></u>
Heat transfer is the phenomenon that occurs when the two objects are in the vicinity of each other and by increasing the area of their contact. Thus, option B is correct.
<h3>What is heat transfer?</h3>
Heat transfer is a process that flows the heat from one system to another, and is because of the difference in the temperature of the two objects that are part of the system.
The methods like conduction, convection, and radiation transfer the heat from the surface area to the other object. The heat gets transferred from the area of high to the low temperature.
Therefore, option B. by increasing the surface area the heat transfer increases.
Learn more about heat transfer here:
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Answer:

Explanation:
<u>1. Energy to heat the liquid water from 55ºC to 100ºC</u>


<u>2. Energy to change the liquid to steam at 100ºC</u>

- n = 10.1g / 18.015g/mol = 0.5606mol

<u>3. Total energy</u>

The pressure of the confined gas will be 769-17 = 752 mmHg
<h3>What is Manometer ?</h3>
Manometer is a U shaped instrument which is used to measure the pressure acting on a column of fluid , a difference in the pressure in the two arms of the manometer causes the liquid to reach different heights.
The difference in the heights of the Hg columns in Diagram B is17 mm-Hg.
the atmospheric pressure is 769 mm-Hg,
the pressure of the confined gas in mm-Hg = ?
The pressure of the confined gas will be 769-17 = 752 mmHg
To know more about Manometer
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