Dimitri Mendeleev was the first to put elements together on a table. He knew there were elements missing but he noticed a trend in some of the elements known at the time. Sodium, Lithium and other alkali metals all have the same properties so he put them under the same column and created other columns with similar attributes (Halogens, Noble gases, Alkaline earth metals). Over the years, new elements were discovered and put into the rough outline that Mendeleev created.
I hope that is about what you wanted.
<h3>
Answer:</h3>
15 moles
<h3>
Explanation:</h3>
The decomposition of boron carbonate is given by the equation;
B₂(CO₃)₃(s) → B₂O₃(s) + 3CO₂(g)
Moles of boron carbonate decomposed is 5.0 mol
To find the moles of CO₂ produced we are going to use the mole ratio.
Mole ratio of B₂(CO₃)₃ to CO₂ is 1 : 3
Therefore;
Moles of CO₂ = Moles of B₂(CO₃)₃ × 3
= 15 mol
Therefore, 15 moles of CO₂ will be produced
Explanation:
Bohr built on Nicholson's idea by adopting the requirement that the angular momentum can have only certain discrete values related to Planck's constant. However Bohr's atom has many orbits for the electrons.
Answer:
Solubility of O₂(g) in 4L water = 3.42 x 10⁻² grams O₂(g)
Explanation:
Graham's Law => Solubility(S) ∝ Applied Pressure(P) => S =k·P
Given P = 0.209Atm & k = 1.28 x 10⁻³mol/L·Atm
=> S = k·P = (1.28 x 10⁻³ mole/L·Atm)0.209Atm = 2.68 x 10⁻³ mol O₂/L water.
∴Solubility of O₂(g) in 4L water at 0.209Atm = (2.68 x 10⁻³mole O₂(g)/L)(4L)(32 g O₂(g)/mol O₂(g)) = <u>3.45 x 10⁻² grams O₂(g) in 4L water. </u>
