Homework Q about finding the sulfide of a metal

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Isabel Day 1D
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Joined: Fri Aug 09, 2019 12:15 am

Homework Q about finding the sulfide of a metal

Postby Isabel Day 1D » Tue Oct 01, 2019 1:41 pm

Question E.15 asks to find the molar mass of the sulfide of M(OH)2, but I don’t understand how to derive a sulfide from this molecule and I’m confused by the wording. First, is sulfide just sulfur attached to a molecule? Second, is the metal the question asks about represented by M in the given molecule? If so, does the letter “M” always represent a metal?

Andrew Jang 4D
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Joined: Sat Aug 17, 2019 12:18 am

Re: Homework Q about finding the sulfide of a metal

Postby Andrew Jang 4D » Tue Oct 01, 2019 1:50 pm

This question requires you to identify the unknown metal M in the metal hydroxide M(OH)2. Subtracting the mass of the (OH)2 part from the total mass given leaves you with a value of about 40.1 g as the molar mass of M. You can find that Ca has a molar mass of about 40.1 g, and its sulfide, CaS, has a molar mass of 72.15 g.
Sulfide is an anion of sulfur S2- so the sulfide of Ca would be CaS. As for M representing metals, I’m not sure if it will always represent metals but you can assume it in the context of this problem.

Alan Huang 1E
Posts: 53
Joined: Wed Sep 30, 2020 9:37 pm

Re: Homework Q about finding the sulfide of a metal

Postby Alan Huang 1E » Wed Oct 07, 2020 1:08 am

In general, sulfide would be sulfur with another metal, and you can find the sulfide of a metal by comparing charges and putting them together.


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