Answer the following stoichiometry question:

how many atoms in 4.75 moles of gold, au?
936 atoms
41.5 atoms
2.86 x 10^ 24 atoms
1.27 x 10^ 23 atoms

2.86 × 10²⁴ atoms of gold

Explanation:

Given data:

Number of moles of gold = 4.75 mol

Number of atoms = ?

Solution:

The given problem will solve by using Avogadro number.

It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.

The number 6.022 × 10²³ is called Avogadro number.

One moles of substance =  6.022 × 10²³ atoms

4.75 moles of gold = 4.75 × 6.022 × 10²³ atoms of gold

28.61 × 10²³ atoms of gold

2.86 × 10²⁴ atoms of gold

i dont know

explanation:

given:

mass of na = 115 g

excess cl2

to determine:

mass of nacl produced

explanation:

given reaction is-

2na(s) + cl2(g) → 2nacl(s)

since cl2 is in excess, na will be the limiting reagent

as per the reaction stoichiometry na: nacl = 1: 1

i.e. moles of na reacted = moles of nacl formed

now, # moles of na = mass of na/atomic mass

                                  = 115 g/23 g.mol-1 = 5 moles

therefore, moles of nacl = 5

molar mass of nacl = 58 g/mol

mass of nacl = 5 moles * 58 g.mol-1 = 290 g

ans: amount of nacl produced = 290 g