Question

Total number of electrons present in 640 u of oxygen gas is??​

Answer 1

Answer:

17 electrons are there in it

Answer 2

GIVEN:

640u of oxygen gas.

To find:

Total number of electrons present in 640u of oxygen gas.

Solution:

Firstly, we have to find out number of moles for 640u of oxygen gas.

formula used is, number of moles = given mass/molecular mass

given mass of oxygen gas = 640u

molecular mass = 32u

putting values , we get

no. of moles = 640/32 = 20 moles

Now, calculate total number of molecules

1 mole of oxygen gas contain= 6.023×10²³molecules

20moles of oxygen gas contains = 20×6.023×10²³

                                                       = 120.46×10²³molecules

Now, 1 molecule of oxygen gas contains = 2 atoms

         120.46×10²³ molecules of oxygen gas contains = 2×120.46×10²³ atoms

1 atom of oxygen contain 8 electrons

2 atoms of oxygen gas contains 16 electrons

2×120.46×10²³atoms of oxygen gas contains electrons = 16×2×120.46×10²³

that means, 38.55×10²¹electrons.

So, total number of electrons present in 640u of oxygen gas is 38.55×10²¹ electrons.