Answer: 100.
Explanation:
1) The subscripts to the right of each element (symbol) in the chemical formula tells the number of atoms of that element present in one unit formula.
2) The unit formula of C₄H₄S₂ is equal to 1 molecule.
3) Therefore, there are 4 carbon atoms, 4 hydrogen atoms and 2 sulfur atoms in each molecule of C₄H₄S₂.
4) Then, you just have to multiply the corresponding subscript of the element times the number of molecules (25 in this case) to find the number of atoms of that kind.
5) These are the calculations for each element in the molecule C₄H₄S₂.
i) C: 4 × 25 = 100
ii) H: 4 × 25 = 100
iii) S: 2 × 25 = 50.
6) The question is about H only, so the answer is that there are 100 hydrogen atoms in 25 molecules of C₄H₄S₂.
Answer is: C. H₂, molecule of hydrogen, g is c<span>hemistry abbreviations or physical state symbol for gas.</span>
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Lithium (Li) is solid (s) element (metal).
Water (H</span>₂O) is liquid (l) compound or molecule.
Lithium hydroxide (LiOH) is aqueous solution (aq). It dissociates in water on lithium cation (Li⁺) and hydroxy anion (OH⁻).
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Answer: A. Liquefy hydrogen under pressure and store it much as we do with liquefied natural gas today.
Explanation:
Current Hydrogen storage methods fall into one of two technologies;
- <em>physical storage</em> where compressed hydrogen gas is stored under pressure or as a liquid; and
- <em>chemical storage</em>, where the hydrogen is bonded with another material to form a hydride and released through a chemical reaction.
Physical storage solutions are commonly used technologies but are problematic when looking at using hydrogen to fuel vehicles. Compressed hydrogen gas needs to be stored under high pressure and requires large and heavy tanks. Also, liquid hydrogen boils at -253°C (-423°F) so it needs to be stored cryogenically with heavy insulation and actually contains less hydrogen compared with the same volume of gasoline.
Chemical storage methods allow hydrogen to be stored at much lower pressures and offer high storage performance due to the strong binding of hydrogen and the high storage densities. They also occupy relatively smaller spaces than either compressed hydrogen gas or liquified hydrogen. A large number of chemical storage systems are under investigation, which involve hydrolysis reactions, hydrogenation/dehydrogenation reactions, ammonia borane and other boron hydrides, ammonia, and alane etc.
Other practical storage methods being researched that focuses on storing hydrogen as a lightweight, compact energy carrier for mobile applications include;
- Nanostructured metal hydrides
- Liquid organic hydrogen carriers (LOHC)
Answer:
The force increases because it is part of a Newton’s third law pair of forces with the force that the star exerts on the planet.
Explanation:
Force between two objects can be expressed by an equation:
F = G • m1 • m2 / r^2,
where m1 and m2 are objects' masses, r is the distance between them, and G is a gravitational constant.
That means that greater the masses or lesser the distance, the force will be greater, and vice versa.
This force exists between any two objects, but is generally extremely weak, so it's best observed with big and large objects with great mass, such as planets and stars.
This force, whatever its magnitude may be, always works on both objects, following the third Newton's law.
So, whatever the force the stat exerts on the planet is, the planet will exert the same amount of force on the star.
