Topic: calculate number of moles (Read 3631 times)

stag · « **on:** April 01, 2011, 06:06:00 AM »

this is the reaction:
Mg (s)+2HCl (aq)--> MgCl2 (aq)+H2 (g)

Mass of Mg: 0.050g
100 ml of 1 M HCl

how many moles of copper are present?

opti384 · « **Reply #1 on:** April 01, 2011, 06:09:54 AM »

First you should show your attempts...

stag · « **Reply #2 on:** April 01, 2011, 06:47:38 AM »

i have no idea, but i guess it would be something like
0.050 g Mg*(1 M /100 mL)

but i dont know.

Nobby · « **Reply #3 on:** April 01, 2011, 07:42:00 AM »

Quote

this is the reaction:
Mg (s)+2HCl (aq)--> MgCl2 (aq)+H2 (g)

Mass of Mg: 0.050g
100 ml of 1 M HCl

how many moles of copper are present?

1st. of April Zero moles of copper will be present.

AWK · « **Reply #4 on:** April 01, 2011, 07:47:00 AM »

this is the reaction:
Mg (s)+2HCl (aq)--> MgCl2 (aq)+H2 (g)

Mass of Mg: 0.050g
100 ml of 1 M HCl

how many moles of copper are present?

You have no copper in this reaction.

Calculations of moles from mass and vice versa is an elementary job in chemistry. You should read any textbook on general chemistry or internet source on stoichiometry, eg: http://www.chembuddy.com/?left=balancing-stoichiometry&right=ratio-proportions

stag · « **Reply #5 on:** April 01, 2011, 08:18:55 AM »

lol sorry i meant Mg.

Nobby · « **Reply #6 on:** April 01, 2011, 08:20:37 AM »

n = m/M n = 0,05 g/24 g/mol = 2,3 mmol