Answer:
Explanation:
Atom X,
Neutron num = 4, Mass num = 7
Therefore, proton number = Mass num - Neutron num
= 7 - 4
= 3
Atom Y,
Neutron num = 5, Mass num = 9
Therefore, proton number = Mass num - Neutron num
= 9 - 5
= 4
1) False. Atom X belongs to group 3 while atom Y belongs to group 4
2) False. Atom X is in a column on the left of Atom Y
3) True. Atom X and atom Y belong to the same period two on the periodic table
4) Fasle. Atom X and Y are not isotopes because they do not have the same atomic number.
Isotopy is a phenomenon whereby atom of same element have same atomic number but different mass number
A first-order reaction is 81omplete in 264s.The half-life for this reaction (i) t 1/2 = =3.465×10 −3 s.to reach 95% Completion = 285 s.
To measure reaction rates, chemists initiate the reaction, measure the concentration of the reactant or product at different times as the reaction progresses,
For a 0-order response, the mathematical expression that may be employed to determine the half of life is: t1/2 = [R]0/2k. For a first-order reaction, the half of-existence is given by: t1/2 = zero.693/ok. For a 2d-order response, the method for the half-life of the response is: 1/okay[R]0
The 1/2-life of a response (t1/2), is the quantity of time needed for a reactant concentration to lower via half of compared to its initial awareness. Its software is used in chemistry and medicine to are expecting the awareness of a substance over time
Half of the lifestyles is the time required for exactly 1/2 of the entities to decay 50%.
Learn more about first order reaction here:-
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The molar mass of sodium is 22.99 ㅤ ㅤ ㅤ 22.99 (28) = 643.72 mol now multiply by avogrados number to find the number of atoms. ㅤ ㅤ ㅤ 643.72 (6.022 x 10^23) = 3.88 x 10^26 number of atoms
Answer:
A car stopped at the top of a hill
Explanation:
Potential energy is the energy that is stored in an object due to its position relative to some zero position.
therefore, the answer is the first option
=> A car stopped at the top of a hill
hope this helps and is right :)
The oxidation number of H is -1.
Sum of the oxidation numbers in each element =
charge of the complex
CaH₂ has 1 Ca atom and 2H atoms. The charge of
the complex is zero. Let’s say Oxidation number of H is "a".
Then,
<span> (+2)
+ 2 x a = 0 </span>
<span> +2 + 2a = 0</span>
2a = -2
a = -1
Hence, the oxidation number of Hydrogen atom in CaH₂ is -1
