Answer:
To determine the amount of heat the gold has absorbed to melt, we simply multiply the mass of the block of ice to the heat of fusion of water which is given above. We calculate as follows:
Heat = 20.0 g (35.4 g)
Heat = 1290 J
Answer: The correct option is (c). The total pressure doubles.
Solution:
Initially, only 4 moles of oxygen gas were present in the flask.
(
) ( according to Dalton's law of partial pressure)
....(1)
= Total pressure when only oxygen gas was present.
Final total pressure when 4 moles of helium gas were added:

partial pressure of oxygen in the mixture :
Since, the number of moles of oxygen remains the same, the partial pressure of oxygen will also remain the same in the mixture.

= Total pressure of the mixture.
from (1)

On rearranging, we get:

The new total pressure will be twice of initial total pressure.
The following are scientific observations which led to development and changes of periodic table: Dmitri Mendeleev is the first periodic table organized 63 known element according to its properties, organized into rows and columns and inscribed name, mass and chemical properties on each element. Julius Lothar Meyer who independently worked in Germany with Ernest Rutherford. They experimented with 38 metals and found out that the positive charge of each element nucleus increased by one from element to element and organized the periodic table that tip to modern explanation of atomic number and the recognition of atomic number was the basis for organization of periodic table.
It is caused by differences in the atmospheric pressure. When a difference in atmospheric pressure exists, air moves from the higher to the lower pressure area, resulting in winds that vary in speed. On Earth, air is also deflected by the Coriolis effect, except exactly on the equator.
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