This problem is asking for the percent by mass of hydrogen in hydrofluoric acid. At the end, the answer turns out to be D. 5% as shown below:
<h3>Percent compositions:</h3>
In chemistry, percent compositions are used for us to know the relative amount of a specific element in a compound. In order to do so for hydrogen, we use the following formula, which can also be applied to any other element in a given compound:

Where
stands for the atomic mass of hydrogen and
for the molar mass of hydrofluoric acid. In such a way, we plug in the atomic masses of hydrogen (1.01 g/mol) and fluorine (19.0 g/mol) to obtain:

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Answer:
In a steam engine into a reciprocating piston cylinder assembly a high pressure steam is been admitted.
Explanation:
Steam engine: High-pressure steam is been injected into a piston-cylinder assembly which is reciprocating in nature. some part of its thermal energy gets converted into movement of the piston to work,When the steam starts expanding to lower pressure.
Apparatus which is separate and a condenser at comparatively low temperature and pressure here steam is passed.The expanded steam can then be made to be free, or, for engine efficiency to be maximum, Rotary motion with a crank-crankshaft assembly similar to that used in automobiles gets transferred from that.
Remaining heat has been now used for warming water.
boiler fired with coal, oil, or natural gas by them the steam gets supplied.
. In many areas, more reliable and economical diesel-electric locomotives gets supplanted by the steam locomotives.
The steam engines today generally are regarded as a unique piece as they are not considered as above reasons are explained.
Nevertheless, the creation of the steam engine played a vital role in the Revolution carried out by the industries by creating a society which now is less dependent on the different windmills, the watermills and mostly the animal power.
Answer:
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Explanation:
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<span>The generalized reaction for chemical decomposition is: AB → A + B
NaOH is sodium hydroxide. When sodium and water is combined it makes sodium hydroxide and hydrogen
When sodium hydroxide decomposes under thermal decomposition, it breaks down into sodium oxide and water.
Thus, </span><span>C) 2NaOH Na2O + H2O</span>