You will need a periodic table to help you answer this problem. The atomic numbers are arrange from lowest to highest in the periodic table. You can locate element number 55 to be Cesium with an atomic weight of 132.905 amu. So, you start from element 56. The following elements are:
56 Barium 137.328 amu
57 Lanthanium 138.905 amu
58 Cerium 140.116 amu
59 <span>Praseodymium 140.908 amu
60 Neodymium 144.243 amu
Neodymium is already greater than 144 amu. Therefore, these elements only include Barium, Lanthanium, Cerium and Praseodymium.</span>
The most accurately represented John Dalton's model of the atom is: C. a tiny, solid sphere with a predictable mass for a given element
<h3>Further explanation</h3>
The development of atomic theory starts from the first term conveyed by Greek scientists who suggested that every substance has the smallest particles so that the word atomos appears, which means it cannot be divided. So, John Dalton, a British scientist put forward the hypothesis about atoms, among others:
- 1. The elements are composed of atoms which are small particles which cannot be subdivided
- 2. Atoms that make up the same element have the same properties, mass, and size, while for different elements, the properties are also different
- 3. Compounds are composed of two or more atoms in a fixed ratio
- 4. In chemical reactions, atoms after and before a reaction cannot be destroyed, only separation and reassembly occur
Point 3 shows the relationship with The Law of Constant Composition of Proust so that further research on atoms is more developed
Dalton's hypothesis is described as a solid sphere like a very small shot put ball or a bowling ball based on Dalton's hobby in bowling
<h3>Learn more</h3>
Bohr's model of the atom
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Rutherford performed the gold foil experiment
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The part of an atom that is mostly empty space
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Keywords: atom, Dalton, a solid sphere, The Law of Constant Composition
The hydrogen bonds that form between water molecules account for some of the essential and unique properties of water. The attraction created by hydrogen bonds keepswater liquid over a wider range of temperature than is found for any other molecule its size.
Hope this helped!
The enthalpy of the creation of Methanol is negative. This means heat is released when the reaction proceeds. You would want to use a low temperature.
Answer:
Explanation:
MnO₂(s) + 4 HCl(aq) = MnCl₂(aq) + 2 H₂O(l) + Cl₂
87 g 22.4 x 10³ mL
volume of given chlorine gas at NTP or at 760 Torr and 273 K
= 175 x ( 273 + 25 ) x 715 / (273 x 760 )
= 179.71 mL
22.4 x 10³ mL of chlorine requires 87 g of MnO₂
179.4 mL of chlorine will require 87 x 179.4 / 22.4 x 10³ g
= 696.77 x 10⁻³ g
= 696.77 mg .