Answer:
Empirical formula is Cr₂O₃.
Explanation:
Given data:
Percentage of Cr = 68.4%
Percentage of O = 31.6%
Empirical formula = ?
Solution:
Number of gram atoms of Cr = 68.4 / 52 = 1.3
2
Number of gram atoms of O = 31.6 / 16 = 1.98
Atomic ratio:
Cr : O
1.32/1.32 : 1.98/1.32
1 : 1.5
Cr : O = 1 : 1.5
Cr : O = 2(1 : 1.5)
Empirical formula is Cr₂O₃.
7.32 moles of Chromium is present in 4.41 × 10²⁴ atoms.
<h3>How to find the number of moles ?</h3>
Number of moles = 
<h3>What is Avogadro's Number ?</h3>
Avogadro's number is the number of particles in one mole of substance. 6.022 × 10²³ is known as Avogadro's Constant / Avogadro's Number.
Avogadro's Number = 6.022 × 10²³
Now put the values in above formula we get
Number of moles =
= 
= 7.32 moles
Thus from the above conclusion we can say that 7.32 moles of Chromium is present in 4.41 × 10²⁴ atoms.
Learn more about the Avogadro's Number here: brainly.com/question/1581342
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Answer:
The chemical reaction in which solid calcium oxide is treated liquid water is an example of Synthesis reaction. Hence, the answer is (D) Synthesis.
Explanation:
The formula of Calcium Oxide is CaO.
The formula of liquid water is H₂O.
Calcium Oxide reacts with water and forms Calcium Hydroxide. The Chemical equation is shown below.
CaO + H₂O --> Ca(OH)₂.
This is a Synthesis reaction because Ca(OH)₂ is synthesized by using Calcium Oxide and water.
The product of this reaction is calcium hydroxide, also known as slaked lime.
Thus, when calcium oxide reacts with water, slaked lime is produced.
Calcium oxide is also known as lime and is most commonly used for many purposes. It can be used for pH correction of water or for its disinfection (with excess lime).
Answer:
84672 J
Explanation:
From the question given above, the following data were obtained:
Height (h) = 72 m
Combined mass (m) = 120 Kg
Acceleration due to gravity (g) = 9.8 m/s²
Energy (E) =?
We can obtain the energy by using the following formula:
E = mgh
Where
E => is the energy.
g => is the acceleration due to gravity
m => is the mass.
h => is the height.
E = 120 × 9.8 × 72
E = 84672 J
Thus, the energy is 84672 J
