[screwed up]

i forgot my chemistry book at school so i searched the net for help with my home work and ccame acroos this place i already did a search for whit ineed help on but i dont understand it


calculate the mass in grams of each of the following


0.75 mol hydrogen sulfide(H[SIZE="1"]2[/SIZE]S)



2.30 mol ethylene glycol(C[SIZE="2"]2[/SIZE]H[SIZE="2"]6[/SIZE]O[SIZE="2"]2[/SIZ


how many grams are there in 1.73  moles of dinitrogen pentoxide

[Will]

To find out the mass in grams of these you multiply the number of moles by the Mr:

0.75 x (1x2 + 32) = 25.5g

2.3 x (12x2 + 1x6 + 16x2) = 142.6g

1.73 x (14x2 + 16x5) = 186.84g

Remember:

mass = moles x Mr

moles = mass / Mr

Mr = mass / moles

Hope thats clear!