The mass of an electron is 9.11 10-28
g. what is the mass of a mole of electrons?

5.489× 10^-4 grams.

Explanation:

Before we solve this question, let us consider one or two facts. The first one is Avogrado's Law. Avogrado's law state that equal volume of all the gases at the same temperature and pressure contains the same number of molecule. The law was generally accepted in the year 1858. Although, the law has been since 1811 by Amedio Avogrado in the University of Turn.

The second is Avogrado's constant. Avogrado's constant is the number of molecule in a substance. It has a value of 6.02214076× 10^23.

So, let us go back to solving the question. From the above explanations, we can see that a mole of a substance or particle contains 6.02214076 × 10^23.

Therefore, the mass of a mole of electrons;

=>>> 6.02214076 × 10^23 × 9.11× 10^-28 gram.

==> 0.000548617023236 grams.

> 5.489× 10^-4 grams.

- decrease the number of plants and animals living in the water.