A gas mixture is composed of 4.3 grams of hydrogen (density at STP= 0.089g/L) and 2.9grams of helium ( density at STP = 0.179 g/L). What is the percentage (v/v) helium in the mixture? SHOW WORK

the correct option is c.

isotopes refers to different forms of the same element with the same atomic number but different mass number as a result of difference in their neutron numbers. isotopes have different relative atomic mass but share the same chemical properties.

metals are good conductor of electricity. it has free electrons on their surface. according to electron pool theory, each atom present in a metal crystal losses all of its valence electron and as a result a pool of free is form. these pool of electrons are free to move and   conduct electricity easily   while making metal as good conductor.

the correct answer is a. the ability of electrons to flow throughout the metal.

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