Q E14

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Emily Orozco L4
Posts: 22
Joined: Fri Sep 28, 2018 12:29 am

Q E14

Postby Emily Orozco L4 » Thu Oct 04, 2018 2:43 pm

This question gives us the molar mass metal hydroxide M(OH)2 is 74.10 g/mol. Then it asks what the molar mass of the sulfide of this metal. Sounds simple, but I'm confused on where the sulfide comes from. Anyone know what it means?

Matthew D 3F
Posts: 14
Joined: Fri Apr 06, 2018 11:02 am

Re: Q E14

Postby Matthew D 3F » Thu Oct 04, 2018 4:11 pm

You have to determine what the metal M is first. Then find the mass of its sulfide, which would be (Metal)S.

305144105
Posts: 32
Joined: Thu May 10, 2018 3:00 am

Re: Q E14

Postby 305144105 » Thu Oct 04, 2018 4:37 pm

1. Find out the mystery metal
74.10g - (15.999*2 + 1.008*2)g = 40.086g
The element with the closest mass to 40.086g is Ca, with a molar mass of 40.078g.

2. Find out the sulfide of Ca (calcium sulfide), which is CaS.

3. Calculate the molar mass of CaS.
=40.078g + 32.065g
=72.143g


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