Chemistry Q assist? (1 Viewer)

[LoveHateSchool]

I'm having trouble with this chem question;

0.30 moles of magnesium oxide is completely dissolved in nitric acid to form a solution of magnesium nitrate. Calculate the moles and masses of:
1) nitric acid required
2) magnesium nitrate formed

I really need this one walk throughed to do the rest of the sheet. I'm not entirely sure I balanced it correctly and if when it mentions masses it's meaning like so many grams of such and such.

Please help? Rep for any kind person.

 

[maths lover]

what textbook is this in, i think it was in my half yearlies. all u need to do is balance the equation. them multiply the mole of magnesium oxide depending on them mole ratio to get the moles of the other components. after this u use the mole formula to calculate the mass.

 

[LoveHateSchool]

Okay I tried what you said and got 0.6 mols, 75.6216 g and 0.3 mols and 44.499 g. I hope that is right!

 

[x_cp3]

a) n HNO3 = 0.60 mol


m = 0.60 x 63.018

For HNO3 the mass you should be 38g (2 sig figs)

b) n Mg(NO3)2 = 0.30 mol

m = 0.30 x molar mass
= 44g (2 sig figs)

 

[LoveHateSchool]

^So even though when I balanced it and there was a two in front of the acid, I don't use that when calculating mass. Ty for the help!

 

[LoveHateSchool]

Needing assistance on another Q, I will love anyone that can help!

A silver coin was analysed and found to contain only silver and copper. 1.580 g of this coin was dissolved in concentrated nitric acid and the resultant solution diluted. Reaction of this solution with excess hydrochloric acid yielded 1.050 g of silver chloride. Calculate the percentage of silver in the sample.

I'm having trouble doing the equation and don't know how to find the percentage of silver...