The correct option is A.
Elements are substances that are made up of atoms of the same type., while compounds are made of two or more atoms of different types.
Some common examples of elements are Iron, Sodium, oxygen, Hydrogen, while NaCl ( Sodium Chloride), Water (H_2O) , Ammonia (NH_3) are compounds.
It can be seen that the compounds are composed of atoms of different substances.
Chlorine is a diatomic molecule, where two Chlorine atoms are bonded by a covalent bond. Since both atoms in a Chlorine molecule are the same, it cannot be called a compound.
Hence Chlorine, though it has more than one atom in its molecular form, is still called element.
17. a
18. c
19. a
20. c
21. c
Answer:
Scientific explanation is aimed at shedding light into natural phenomenon through the use of measurement results and observations.
The groups to benefit from the claim are:
- People who sell coffee with caffeine
- Diners that serve coffee with caffeine
- Soda manufacturers that sell caffeinated drinks
- Manufactures of caffeinated energy sports drink
The above selection are correct due to the following reasons:
The claim in the question is: <em>"Caffeine improves mental alertness and motor coordination"</em>
The assertions of the claim are:
- Caffeine improves mental alertness, meaning that by taking caffeine, a person becomes more alert and/or aware of the environment as well as being able to keep up better at task, which are desirable for work related activities
- Caffeine improves motor coordination; Motor coordination refers to the ability to involve multiple parts of the body to achieve complex motion. The ability to improve motor coordination can create demand for caffeine among active people
Based on the above association of caffeine to benefits that are desired by active people, (working people that generate income), the groups that would benefit most from the claim are, the dealers in caffeinated products including:
- <u>People who sell coffee with caffeine</u>
- <u>Diners that serve coffee with caffeine</u>
- <u>Soda manufacturers that sell caffeinated drinks</u>
- <u>Manufactures of caffeinated energy sports drinks</u>
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Learn more about the scientific explanations here:
brainly.com/question/6872942
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Answer:
a) E = 6.4 1019 J b) v = 0.69 10⁴4 m / s
Explication
a) convert E = 4.0 eV
1 eV = 1.6 10⁻¹⁹ J
E = 4.0 eV (1.6 10⁻¹⁹ J / 1 eV)
E = 6.4 10⁻¹⁹ J
b) Suppose we have a frontal shock and all the kinetic energy of oxygen is transferred to Cs
Ei = K = ½ m v²
Ef = 6.4 10⁻¹⁹ J
½ m v² = 6.4 10⁻¹⁹
The oxygen mass of the periodic table is
PA = 15,999 u
1u = 1.660 10⁻²⁷ kg
Pa = 15,999 1,660 10⁻²⁷ kg
m= Pa = 26,558 10⁻²⁷ kg
Let's calculate the speed
v2 = 2 / m 6.4 10⁻¹⁹
v2 = 2 / 26,558 10⁻²⁷ 6.4 10⁻¹⁹ =
v = √0.4819 10⁸
v = 0.69 10⁴4 m / s
yes but all of these are correct answers