Answer:
- <em><u>Mendeleev produced the first orderly arrangement of known elements.</u></em>
- <em><u>Mendeleev used patterns to predict undiscovered elements.</u></em>
Explanation:
- <u>Mendeleev produced the first orderly arrangement of known elements and used patterns to predict the undiscovered elements.</u>
Those two statments are true.
For the time being there were some 62 known elements. Before Medeleev some schemes to order part of the elements were proposed, but Medeleev showed the relationship between the atomic mass and the properties of the elements (supports second choice). This arrangement is known as the periodic table.
More importantly, Mendeleev predicted correctly the existance and properties of unknown elements, which is his major contribution: he left blanket spaces which where gradually filled when new elements where discovered (this supports the fourth choice).
The first modern chemistry book was written by Antoine Lavoisier (this discards first option).
Mendeleev ordered the elements by increasing mass number (this discards third choice), which was corrected later by the scientist Henry Moseley, who ordered the elements by increasing atomic number (number of protons).
Isotopes were not known by Mendeleev times, so this discards the last option.
<span>Various gases and liquids have different densities and combustion points.</span>
By looking at a periodic table, we can conclude that the molar mass of lithium is 6.94g, the molar mass of zinc is 65.38g, and the molar mass of gold is 196.97g. Each of these quantities contains 6.02×1023 atoms of that particular element. The units for molar mass are grams per mole, or g/mol.
So The answers are Lithium, Gold, Zinc
Hope This Helps
~Zero~
Geometric isomers is defined as "each of two or more compounds that differ from each other in the arrangement of groups with respect to a double bond, ring, or other rigid structure."
I hope this answer helped you! If you have any further questions or concerns, feel free to ask! :)
Answer:
b. 0,99atm
c. Answer is in the explanation
d. Answer is in the explanation
Explanation:
b. Using Gay-Lussac's law:
P₁T₂ = P₂T₁
P₁: 0,70 atm; T₂: 425K; P₂: ??; T₁: 299K
0,70atm×425K / 299K = <em>0,99 atm</em>
c. Using kinetic molecular theory, the increasing of temperature increases the kinetic energy of gas particles and if kinetic energy increases, the pressure increases. That means the increasing of temperature increases the pressure in the system.
d. Now, the increases in kinetic energy of gases increase the collisions betwen particles. As these intermolecular forces that are not taken into account in ideal gas law, the observed pressure will be different to the pressure predicted by ideal gas law.
I hope it helps!
