Answer:
There are 7.00 × 10²² H⁻ ions in 5.22 g of SrH₂.
First, we will convert 5.22 g of SrH₂ to moles of SrH₂ using its molar mass (89.64 g/mol).
Then, we want to convert 0.0582 moles of SrH₂ to molecules of SrH₂ using Avogadro's number: there are 6.02 × 10²³ molecules of SrH₂ in 1 mole of molecules of SrH₂.
The molar ratio of SrH₂ to H⁻ is 1:2. The number of H⁻ ions in 3.50 × 10²² molecules of SrH₂ is:
There are 7.00 × 10²² H⁻ ions in 5.22 g of SrH₂
