# Emperical FormulaWatch

#1
Can someone help me on this question. I keep getting MgH4, and the answer is MgH2.

1.2g of Magnesium reacts with 0.2g of hydrogen. Work out the formula.

My solution:

1.2/24 : 0.2/1
0.05: 0.2
1:4

0
12 years ago
#2
this has appeared before on a previous thread - the answer DOES come out to MgH4 because the question is wrong
Books do occasionally contain misprints - "we all make mistakes" said the Dalek climbing off the dustbin... (Courtesy Jasper Carrott)
0
12 years ago
#3
(Original post by Srathmore)
Can someone help me on this question. I keep getting MgH4, and the answer is MgH2.

1.2g of Magnesium reacts with 0.2g of hydrogen. Work out the formula.

My solution:

1.2/24 : 0.2/1
0.05: 0.2
1:4

Oh yeah this has been posted before...
0
#4
(Original post by Srathmore)
Can someone help me on this question. I keep getting MgH4, and the answer is MgH2.

1.2g of Magnesium reacts with 0.2g of hydrogen. Work out the formula.

My solution:

1.2/24 : 0.2/1
0.05: 0.2
1:4

Looking back at this question, i think the answer would be MgH2

You have to consider:
Mg + H2, (not Mg + H ... as i previously did)
1.2g : 0.2
24 : 2
1.2/24 : 0.2/2
0.05:1
1:2

Therefore MgH2.
0
12 years ago
#5
(Original post by Srathmore)
Looking back at this question, i think the answer would be MgH2

You have to consider:
Mg + H2, (not Mg + H ... as i previously did)
1.2g : 0.2
24 : 2
1.2/24 : 0.2/2
0.05:1
1:2

Therefore MgH2.

NO, this thread has been played to death - the question is wrong and the answer comes to MgH4 which is clearly wrong!!!

even if you consider H2 then you are calculating the number of moles of H2 which comes to twice as many as Mg therefore Mg(H2)2 which is still MgH4

is this a wind up? (looks for hidden cameras)
0
12 years ago
#6
(Original post by charco)
NO, this thread has been played to death - the question is wrong and the answer comes to MgH4 which is clearly wrong!!!

even if you consider H2 then you are calculating the number of moles of H2 which comes to twice as many as Mg therefore Mg(H2)2 which is still MgH4

is this a wind up? (looks for hidden cameras)
yeah you're right
0
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