A (pretty sure) PLEASE MAKE ME BRAINLIEST
Answer:
You are really and i mean very dumb and extremely 100 percent stupid.
Explanation:Yep you sure the most stupidest boy in the world.
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Periodic table is the representation of elements in an order
The history of periodic table can be summarized as
a) 1829 : Johann Dobereiner proposed the triad rule. According to him we can classify the elements in a triad where the atomic mass of middle element is average of atomic mass of the near by two atoms.
For example : Li, Na and K is a triad. Where atomic mass of Na is average of atomic mass of K
atomic mass of Na = 7+ 39 / 2 = 23
However, with the further discovery of elements the law was rejected.
b) 1864 : John Newland proposed the law of octave. According to him we can arrange the elements in a set of seven elements where the property of second set of seven elements will resemble the properties of first of seven elements or property will be repeated after seven elements. This was also rejected due to its limited applicability.
c) Meyer : He arranged some 28 elements into six different families based on their atomic masses. The members of each familiy shared some common properties.
d) 1869 : Mendleev : He actually developed a periodic table based on atomic mass of elements. He arranged the elements into groups and periods. He even left space for some undiscovered elements, which were later on discovered.
e) 1916 : Henry Moseley : He finally arranged elements based on their atomic number based on X-ray studies. He proposed the modern periodic law that the periodic properties of elements are due to atomic number of elements.
Answer:
11.3 g of H₂O will be produced.
Explanation:
The combustion is:
2C₈H₁₈ + 25O₂→ 16CO₂ + 18H₂O
First of all, we determine the moles of the reactants in order to find out the limiting reactant.
8 g / 114g/mol = 0.0701 moles of octane
37g / 32 g/mol = 1.15 moles of oxygen
The limiting reagent is the octane. Let's see it by this rule of three:
25 moles of oxygen react to 2 moles of octane so
1.15 moles of oxygen will react to ( 1.15 . 2)/ 25 = 0.092 moles of octane.
We do not have enough octane, we need 0.092 moles and we have 0.0701 moles. Now we work with the stoichiometry of the reaction so we make this rule of three:
2 moles of octane produce 18 moles of water
Then 0.0701 moles of octane may produce (0.0701 . 18)/2= 0.631 moles of water.
We convert the moles to mass → 0.631 mol . 18 g/1mol = 11.3 g of H₂O will be produced.
Answer:
205 K (to 3 significant figures)
Explanation:
Assuming that 4 moles of the gas behaves like an ideal gas and obey the kinetic molecular theory.
Let's apply the ideal gas law, pV= nRT.
Here p denotes the pressure of the gas, V is for volume, n is the number of moles of the gas, R is the universal gas constant and T is the temperature.
Substitute the given information into the equation:
5.6 atm ×12 L= 4 mol ×R ×T
Since pressure is in atm and volume is in L, we can use R= 0.08206 L atm K⁻¹ mol⁻¹.
5.6 atm ×12 L= 4 mol ×0.08206 L atm K⁻¹ mol⁻¹ ×T
T= 67.2 ÷0.32824
T= 204.73 (5 s.f.)
T= 205 K (3 s.f.)
