Answer:
The temperature must be changed to 4 times of the initial temperature so as to keep the pressure and the volume the same.
Explanation:
Pressure in the container is P and volume is V.
Temperature of the helium gas molecules =
Molecules helium gas = x
Moles of helium has = 
PV = nRT (Ideal gas equation)
...[1]
After removal of helium gas only a fourth of the gas molecules remains and pressure in the container and volume should remain same.
Molecules of helium left after removal = 
Moles of helium has left after removal = 
...[2]
The temperature must be changed to 4 times of the initial temperature so as to keep the pressure and the volume the same.
Answer:
The density of igneous rocks is related to its color. Darker colored rocks have a higher density because of its greater mineral and iron content. Its characteristics is opposite compared to lighter colored rocks that have less density because of lower mineral and iron content
Answer:
105
Explanation:
Density = mass/volume
therefore volume = mass/density
826/7.9=105 (To three significant figure)
Answer:
B. only particle Z
Explanation:
In the case of subatomic particles, those positive and neutral are located in the nucleus, and those with a negative charge on the outside.
atoms are made of 3 types of subatomic particles; electrons, protons and neutrons
atomic number is the number of protons. atomic number is characteristic for the element. In ground state atoms, the number of electrons and protons are the same.
the electronic configuration of Ca in the ground state is
Ca - 1s² 2s² 2p⁶ 3s² 3p⁶ 4s²
when Ca loses its 2 valence electrons, it becomes positively charged and the electronic configuration becomes
Ca - 1s² 2s² 2p⁶ 3s² 3p⁶
number of electrons in Ca²⁺ is 18
the atom in the ground state would have the same number of electrons and protons. Therefore number of protons are 18. then the atomic number of the element is 18
the atom having an atomic number of 18 is Ar.
the answer is 1) Ar
