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2 Answers
- 10 years agoFavorite Answer
It's a stoichiometry problem. Each formula unit of strontium hydride contains two hydride ions. So, dividing the mass (4.83g) by the molecular weight (89.636g/mol) shows that we have .0539mol SrH2. Multiplying by a stoichiometric coefficient of 2 H- ions per mole of SrH2 gives us .108 moles of hydride ions. If you want the number instead of the amount, multiply that by Avogadro's constant.
(.1077mol * 6.02214*10^23 ions /mol = 6.4 * 10^22 H- ions)
Source(s): Ebbing-Gammon, HBW Soles - 10 years ago
First you convert the grams of srH2 into moles using n=m/M where n is moles, m=mass in grams and M=molar mass. Since each molecule has 2 hydrogens, that means that you have to multiply the number of moles from the previous step by 2 to get moles of hydrogen. Once you do this, you have your answer.
